INTRODUCTION
Floras of the Pennsylvanian-Permian transition are 
broadly represented across the equatorial regions of the 
supercontinent of Pangea (e.g., Kerp and Fichter, 1985; 
Tidwell, 1988; Hunt and Lucas, 1992; Blake and others, 
2002; Roscher and Schneider, 2006; Wagner and Álvarez-
Vázquez, 2010; Blake and Gillespie, 2011; Lupia and Ar-
mitage, 2013; Opluštil and others, 2013; Tabor and others, 
2013; Wang and Pfefferkorn, 2013). The content of these 
floras is similar, especially in the Euramerican areas, which 
stretch from the present-day western United States through 
Eastern Europe (figure 1). Many taxa typical of Eurameri-
can floras also occur in Chinese/Cathaysian assemblages 
(Hilton and Cleal, 2007). On average, these floras reflect 
the long-term, multi-million-year trend of increasing arid-
ity that characterized much of the Pangean tropics begin-
ning in the late Middle Pennsylvanian (Cecil, 1990), par-
ticularly in the central and western areas. However, the 
floras also reveal a considerable amount of spatio-temporal 
variability in expression of this trend. In western Pangea 
in particular, especially in areas some distance north of the 
equator, the long-term aridification trend may have been 
reversed in the short term by a limited period of increased 
moisture input around the Pennsylvanian-Permian bound-
ary (Tidwell, 1988; Soreghan and others, 2002).
This article describes fossil plants from three areas 
in San Juan County, Utah, from approximately the Penn-
sylvanian-Permian boundary. These floras are of inter-
est for several reasons. Perhaps most importantly is their 
paleogeographic position, in far western Pangea. Based on 
sedimentary patterns and studies of paleosols, this area ex-
perienced extreme aridity through most of the later Penn-
sylvanian, but apparently experienced a return of sufficient 
moisture during latest Pennsylvanian and earliest Permian 
to dramatically alter the regional environments before arid 
conditions returned (Soreghan and others, 2002; Tabor and 
Poulsen, 2008; Jordan and Mountney, 2012). The period 
of resurgent moisture was wet enough to support some 
species typically found in wetland floras of the same age, 
in the more central parts of the Pangean supercontinent. 
The floras found in San Juan County are mixed, including 
species typical of seasonally dry environments as well as 
the wetland taxa. Mixed assemblages strongly suggest an 
overall landscape of seasonal moisture limitation, within 
which the wetland taxa were confined to parts of the land-
scape with high-water tables, such as the margins of rivers 
and streams or low-lying parts of floodplains. Such places 
are also the most favorable for preservation, thus making 
the wetland plants “more apparent” than might be expected 
were the fossil flora drawn proportionally from all habitats 
on the landscape of the time. It is difficult to account for 
the presence of taxa adapted to periodically dry substrates 
within overall wetland landscapes characterized by humid 
FOSSIL FLORAS FROM THE PENNSYLVANIAN-PERMIAN 
CUTLER GROUP OF SOUTHEASTERN UTAH
ABSTRACT 
Fossil plants have been collected and described from strata near the Pennsylvanian-Permian boundary in three 
areas of San Juan County, Utah. Collections made near Indian Creek east of Canyonlands National Park comprise 
mainly tree fern foliage and sphenopsids from one stratigraphic level, and large logs of conifers with rare conifer 
foliage from a higher level. A site on Lime Ridge west of Bluff, Utah, yielded abundant large branches of walchian 
conifers together with calamitaleans and cordaitalean foliage. Sites in Valley of the Gods State Park, west of Lime 
Ridge, produced mainly stems, with variable occurrences of foliage. Most of the stems are calamitalean or the 
large tree fern Caulopteris, but a single medullosan pteridosperm specimen also was found, as were several small 
fragments of the lycopsid Sigillaria. Tree fern foliage, Pecopteris, rare neuropterid foliage, and fragments of leaf-
bearing conifer branches also were identified. Thus, our collections contain a mixture of plants adapted to season-
ally dry conditions (conifers and possibly cordaitaleans) and those requiring wet substrates (calamitaleans, tree 
ferns, lycopsids and pteridosperms). Red beds, dune sands, loess, and gypsum indicate aridity, on average, but with 
intervals of more humid conditions. The combination implies an arid eolian depositional system traversed at times 
by streams sourced on the Uncompahgre highland.
by
William A. DiMichele1*, C. Blaine Cecil2, Dan S. Chaney1, Scott D. Elrick3, and W. John Nelson3
1Department of Paleobiology, National Museum of Natural History, Smithsonian 
Institution, Washington, DC
2U.S. Geological Survey National Center, 12201 Sunrise Valley Drive, Reston, VA
3Illinois State Geological Survey, University of Illinois, IL
*Corresponding author; dimichel@si.edu
DiMichele, W.A., Cecil, C.B., Chaney, D.S., Elrick, S.D., and Nelson, W.J., 2014, 
Fossil floras from the Pennsylvanian-Permian Cutler Group of southeastern 
Utah, in MacLean, J.S., Biek, R.F., and Huntoon, J.E., editors, Geology of 
Utah’s Far South: Utah Geological Association Publication 43, p. 491–504.
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climates; in contrast, localized wetter areas, within other-
wise seasonally dry backgrounds, are commonly found and 
permit wetland-plant survival in isolated patches or narrow 
corridors—as in the western United States today.
Herein we report floras from three areas in present 
day San Juan County, Utah: Lime Ridge, Valley of the 
Gods, and Indian Creek (figure 2). These floras, composed 
predominantly of walchian conifers, calamitaleans and ma-
rattialean tree ferns, complement a richer and better-pre-
served flora described by Tidwell (1988) from the Moab 
area northeast of Indian Creek. In addition, we note evi-
dence for widespread vegetation, even in areas where no 
macroflora has been identified (or preserved).
GEOLOGY
Tectonic Setting
The localities discussed in this paper are situated in 
the southwestern part of the Paradox Basin, a Pennsylvani-
an-age feature that underlies much of southwestern Colo-
rado and southeastern Utah (figure 2). The Paradox Basin 
is a intraforeland flexural basin (Barbeau, 2003) separated 
from the Uncompahgre Uplift to the northeast by a major 
fault zone. Development commenced during the Middle 
Pennsylvanian, when cyclic carbonate, evaporite, and clas-
tic strata, more than 2 kilometers thick in places, accumu-
lated in the nearly land-locked basin. By Late Pennsylvan-
ian time, tectonism was winding down and sedimentation 
outstripped subsidence. During the Pennsylvanian-Permi-
an transition, the study area became the site of fluvial, eo-
lian, and restricted marine sedimentation under a climatic 
regime that fluctuated from arid to subhumid (Baars and 
Stevenson, 1981; Dubiel and others, 1996; Soreghan and 
others, 2002).
Stratigraphy
Stratigraphic nomenclature applied to latest Pennsyl-
vanian and earliest Permian rocks in the Paradox Basin is 
complex, and some aspects remain controversial. A full ex-
position is beyond the scope of this paper, but see Soreghan 
and others (2002) and Huntoon and others (2002). Broadly 
speaking, during the Late Pennsylvanian time dominantly 
marine strata gradually gave way to alternating layers of 
gray marine limestone and red terrestrial siliciclastics, with 
the latter increasing through time. Various authors applied 
the names Honaker Trail, Rico, and Elephant Canyon for-
mations to the transitional rocks. Proximal to the systemic 
boundary, the succession consists entirely of red beds that 
have been assigned to the Cutler Group or Formation. Unit 
boundaries are time transgressive and intertongue on a 
large scale (figure 2). As discussed briefly below, the fossil 
floras highlight some ambiguities in the way time horizons 
have been drawn through the various, often environmen-
tally distinct strata.
Lime Ridge and Valley of the Gods
Our collections from Valley of the Gods and north of 
Snake Canyon at Lime Ridge, southern San Juan County, 
Figure 1.  Paleogeographic reconstruction of Pangea and major oceanic areas at the approximate time of the transition from the Penn-
sylvanian to Permian. Study area marked by white circle. Map courtesy of Ron Blakey, Colorado Plateau Geosystems, Inc.
MacLean, J.S., Biek, R.F., and Huntoon, J.E., editors
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are from the Halgaito Formation (figures 2 and 3). In Valley 
of the Gods, the Halgaito and overlying Cedar Mesa Sand-
stone have eroded to pinnacles and buttes that have been 
given fanciful names such as Santa Claus and Rudolph, De 
Gaulle and His Troops, and Rooster Butte. These natural 
sculptures are reminiscent of those in the better-known 
Monument Valley to the south in Arizona, but there the pin-
nacles are carved from the younger Organ Rock Formation 
and De Chelly Sandstone. 
Variously classified as a formation, member, or tongue 
of the Cutler Group or Formation (Baker and Reeside, 
1929; O’Sullivan, 1965; Dubiel and others, 1996), the Hal-
gaito is 70-120 meters thick and consists of predominantly 
red mudstone, siltstone, sandstone, and minor conglomer-
ate (figure 3). Below the Halgaito is the Rico Formation, a 
unit of terrestrial red beds alternating with thin but wide-
spread layers of fossiliferous marine limestone. The Rico-
Halgaito contact is time transgressive. Above the Halgaito 
is the Cedar Mesa Sandstone, which undergoes a marked 
facies change between Valley of the Gods and Lime Ridge. 
In the type area north of Valley of the Gods, the Cedar 
Mesa Sandstone is predominantly an eolian facies of cliff-
forming sandstone that is light colored, fine grained, and 
exhibits giant-scale cross-bedding. Within a few kilometers 
eastward, the Cedar Mesa Sandstone changes to interbed-
ded sandstone, mudstone, siltstone, gypsum, and thin lay-
ers of cherty limestone. A measured section through the 
Cedar Mesa Sandstone at Lime Ridge is 257 to 278 meters 
thick, depending on the choice of upper contact. 
The age of the Halgaito Formation is loosely con-
strained. According to Vaughn (1962), its vertebrates point 
to Wolfcampian (early Permian) age. Invertebrate fossils 
from the uppermost Rico limestone beds favor a Late Penn-
sylvanian age, but an earliest Permian age cannot be ruled 
out (O’Sullivan, 1965). 
A Halgaito section measured north of Snake Canyon 
at Lime Ridge (figures 3 and 4.1) is 76 meters thick and 
contains about 50% sandstone that is light gray to medium 
reddish brown, very fine to fine grained, and calcareous. 
Low-angle cross-bedding and ripple marks are common, as 
are shallow channels. Other features include mud cracks, 
indistinct burrows and root traces, and zones of carbon-
ate nodules (pedogenic?). Most sandstone apparently rep-
resents deposits of small streams, which is where plant 
Figure 2.  Stratigraphic terminology used and geographic location of samples discussed and in this paper. IC = Indian Creek, LR = Lime 
Ridge, SH = Setting Hen, SS = Seven Sailors.
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fossils are preserved (figure 4.2), but a few massive beds 
may represent accumulations of wind-blown sand and silt. 
Separating sandstone beds are intervals of mudstone and 
siltstone, largely red to brown with gray mottling. Some 
beds have blocky structure and indistinct roots and bur-
rows, suggestive of weak soil development. Beds of mas-
sive siltstone, especially a prominent orange bed near the 
base of the Halgaito, may have formed as eolian deposits 
(loess). Beds of silty, micritic limestone less than 20 cen-
timeters thick and lenses of intraformational conglomerate 
are rare constituents. 
We collected fossil plants from the Halgaito: (1) on 
the east flank of Lime Ridge along U.S. Highway 163, (2) 
near Setting Hen Butte in Valley of the Gods, and (3) near 
Seven Sailors Butte in Valley of the Gods. As best we can 
determine, all three sites occur between 20 and 25 meters 
above the base of the Halgaito, and thus are in the same 
plant-bearing interval of small channels (figure 3). The host 
rock in all cases is fine-grained, thin- to medium-bedded 
sandstone sometimes having clay drapes along bedding 
surfaces, which enhance fossil preservation. It is arranged 
in a series of crosscutting shallow channels, each a meter 
or so deep and 10 to 20 meters wide. It cannot be estab-
lished, however, that the channel deposits at Lime Ridge 
belong to the same southwest trending, sandstone-filled 
channel or channel complex identified at both Setting Hen 
Butte and Seven Sailors Butte (figures 2, 3, and 5.1-5.3). 
Shark teeth and unidentified bone fragments occur in the 
basal conglomerate of a channel near Seven Sailors Butte; 
the original environment of deposition of these vertebrate 
remains cannot be established given their preservation in 
channel-lag deposits. Diplichnities, the trackway of a giant 
myriapod, was collected at Lime Ridge (Chaney and oth-
ers, 2013).
Figure 3.  Measured lithological sections from the east flank of Lime Ridge (Highway 163, just north of Snake Canyon), Setting Hen Butte 
(Valley of the Gods) and Cedar Point. Scale in meters.
MacLean, J.S., Biek, R.F., and Huntoon, J.E., editors
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Indian Creek
Indian Creek is a northwest-flowing tributary of the 
Colorado River in northern San Juan County. Our collec-
tions were made near the stream approximately 19 kilom-
eters northeast of the junction of the Green and Colorado 
Rivers (figure 2). 
Plant fossils occur in rocks that Huntoon and others 
(1982) mapped as “undivided Cutler-Cedar Mesa Sand-
stone transition.” For brevity, we refer to this unit as the 
Cedar Mesa Sandstone. Most of our collections came 
from the basal 10 meters of the Cedar Mesa Sandstone, 
but two collections of mineralized logs were made 20 to 
30 meters above the base. Plant compression fossils occur 
in thin-bedded siltstones, which fill scours and are inter-
calated with thin, trough-shaped beds of sandstone. These 
lie immediately above rooted, calcic Vertisols and below 
cross-bedded sandstones of possible eolian origin (figures 
6.1-6.4). The plant-bearing deposits appear to constitute a 
floodplain sequence.
Based on mapped elevation change and structural dip 
of 2° to the northeast, the Cedar Mesa Sandstone is approx-
imately 120 meters thick in the collecting area. This unit is 
composed of sandstone, siltstone, and mudstone in various 
shades of red. The lower half of the formation is roughly 
90% sandstone in beds as thick as 20 meters, which erode 
to a series of joint-bounded buttes and monoliths. Most of 
the sandstone is light colored, fine grained, well sorted, and 
exhibits cross-bedding in sets many meters thick. Inter-
preted as eolian dunes, these strata locally contain gypsum 
crystal casts, chert formed in interdune sabkhas, and logs of 
silicified wood. Other sandstone in the lower Cedar Mesa 
Sandstone is deeper reddish brown and displays low-angle 
Figure 4.  East flank of Lime Ridge. 1. General view of the fossil-bearing channel deposit, from which plant collections (USNM locality 
43579) were made, forming the low ridge in the lower portion of the outcrop (white arrow). 2. Detail of fossiliferous channel sediments, 
comprising a trough-shaped sandstone-filled scour. 3. Cordaites sp. foliage. USNM559863. 4. Annularia sp. USNM559862. 5. Walchia 
sp. Mat of branches, including a branch base (center left). Pencil barrel for scale in upper right corner. USNM559864. 6. Walchia sp. 
Ultimate branchlet. Field photograph.
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Figure 5.  Valley of the Gods. 1. Seven Sailors Butte. Fossiliferous channel edge marked by white arrow. Channel deposits extend to 
the right as resistant ledge. 2. Setting Hen Butte. Tabular, planar-laminated sandstone from which Walchia sp. (5.9) was collected. 3. 
Setting Hen Butte. View of fossiliferous channel, base marked by white arrow. 4. Calamites gigas. Field photograph. 5. Calamites gigas. 
Field photograph. 6. Caulopteris sp. USNM559861. 7. Medullosan pteridosperm stem with reflexed leaf petiole; a less obvious petiole is 
present in the lower part of the stem. Field photograph. 8. Sigillaria brardii. Scale = 1 centimeter. Field photograph. 9. Walchia sp. Scale 
= 1 centimeter. Field photograph.
MacLean, J.S., Biek, R.F., and Huntoon, J.E., editors
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Figure 6.  Indian Creek. 1. Collecting area USNM locality 43582. Collections made in left side of area. 2. Collecting site USNM locality 
43582, closeup. 3. Collecting area USNM locality 43577. 4. Collecting site locality 43577, closeup. Plants come from clayey shale im-
mediately below the sandstone ledge. 5. Pecopteris sp., showing three pinnae. USNM559865. 6. Pecopteris sp. Closeup of central pinna 
illustrated in 6.5. 7. Fertile pecopterid, Asterotheca sp., pinna fragment. USNM559866. Scale bars in 5-7 = 1 centimeter.
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cross-bedding along with cut-and-fill features characteris-
tic of fluvial channels. Less resistant to erosion, most mud-
stone and siltstone is also dark reddish brown, non-fissile, 
and non-fossiliferous. Locally, deposits of laminated to 
thinly bedded shale and siltstone have yielded fossil fol-
iage and stems.
Underlying the Cedar Mesa Sandstone at Indian 
Creek is the Elephant Canyon Formation, which consists 
of terrestrial red beds alternating with thin but widely trace-
able beds of marine limestone (Baars, 1962, 1991). The up-
per contact is drawn at the top of the stratigraphically high-
est limestone (Huntoon and others, 1982). The Elephant 
Canyon resembles the Rico Formation, but evidently is 
younger, as the Elephant Canyon intertongues southward 
with the Halgaito Formation and yields both Virgilian and 
early Wolfcampian fusulinids (Loope and others, 1990; 
Sanderson and Verville, 1990). On this basis, fossil plants 
from the basal Cedar Mesa Sandstone are definitely Per-
mian, and likely are younger than those from Lime Ridge 
and Valley of the Gods.
FOSSIL FLORAS
Floras from all three sites are noteworthy for contain-
ing a distinct wetland element. This finding contrasts with 
the abundant evidence of Late Pennsylvanian and early 
Permian climatic aridity over large areas of western Pan-
gea, exemplified by extensive deposits of loess, dune sands 
and evaporites (e.g., Langford and others, 2008; Tabor and 
Poulsen, 2008; Sur and others, 2010; Dubois and others, 
2012; Jordan and Mountney, 2012). The typically xeromor-
phic, seasonally dry floral component of our floras varies 
in abundance, type of preservation, and implications about 
the landscape in which it existed. Although none of these 
fossils are museum-quality “trophies”, they yield valuable 
insights into the landscape and climate of western equato-
rial Pangea during this time.
All collections described in this paper are housed in 
the U.S. National Museum of Natural History, Paleobotani-
cal Collections, under the following locality numbers:
1. Lime Ridge—43579
2. Setting Hen Butte—43580-43581
3. Seven Sailors Butte—43583-43686
4. Indian Creek lower level—41414-41419, 41652,    
43577, 43582
5. Indian Creek upper level—41413, 41420, 43578
Lime Ridge
The flora from the shallow-channel complex at the 
Lime Ridge site is dominated by walchian conifers, but 
also contains a significant component of calamitaleans, in-
cluding foliage, and rare cordaitalean foliage (figures 4.3-
4.6). Walchian specimens occur as fragments of branches 
and as whole lateral branch systems, sometimes densely 
matted. They are present throughout the site on many bed-
ding surfaces. Walchians correlate closely with physical 
environmental indicators of seasonal aridity (Falcon-Lang 
and Bashforth, 2005; Bashforth and others, 2014), most-
ly likely dry subhumid to semiarid climates (sensu Cecil 
and Dulong, 2003). Calamitalean fossils, including large 
branches with attached foliage, are common. Although 
these fossils are not well enough preserved for specific 
identification, their ovoid foliage whorls and large number 
of leaves resemble Annularia carinata. Cordaitalean foli-
age shows characteristic strap-shaped, elongate leaves with 
bluntly pointed tips but, again, cannot be identified to the 
species level. On the basis of thousands of observations 
from across Euramerica over the past 150 years, calami-
taleans can be regarded confidently as preferring habitats 
with high soil moisture. The group is complex, however, 
and many of the species, such as those found in the deposits 
described here, appear to have been able to colonize rapid-
ly shifting substrates (Gastaldo, 1992), including within ac-
tive rivers, and to have been able to grow in the wetter parts 
of otherwise dry landscapes (DiMichele and others, 2006). 
Cordaitaleans, in contrast to both walchian conifers and ca-
lamitaleans, are, as a group, exceptionally widespread in 
their environmental preferences, growing everywhere from 
swampy wetlands and peat-forming settings to upland ar-
eas (e.g., Falcon-Lang and Bashforth, 2005; Opluštil and 
others, 2009; Raymond and others, 2010).
Valley of the Gods
Collections from Valley of the Gods (figure 5.4-5.9) 
consist mostly of large axes (stems) preserved as casts in 
sandstone, along with rare fragments of foliage. The most 
abundant stems belong to Calamites gigas, a large diam-
eter calamitalean thought to have lived under conditions 
of moisture stress (see Barthel and Rößler, 1996; Naugol-
nykh, 2005). Also common at Setting Hen and Seven Sail-
ors Buttes are large diameter stems of marattialean tree 
ferns, of the Caulopteris type. The most diagnostic feature 
of Caulopteris is leaf scars (one of which is marked by a 
white arrow in figure 5.6) arranged helically around the 
stem (if arranged in two opposite rows the stems would 
be attributable to Megaphyton). A few fragments of Pecop-
teris, tree-fern foliage occur in association with the stems. 
A single stem attributable to a medullosan pteridosperm 
(figure 5.7) was found at Seven Sailors Butte. This stem is 
> 7 centimeters in diameter and is characterized by persist-
ent, attached basal portions of fronds (one of which can 
be seen clearly and one of which is hinted at lower on the 
stem); the locations of other possibly attached leaf bases 
are weakly marked, as can be typical of these stems. No 
unequivocal pteridosperm foliage was identified at Valley 
of the Gods, though some poorly preserved specimens of 
possible pteridosperm affinity were found.
Small bits of other wetland plants were identified 
from Valley of the Gods. Most significant are a few speci-
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mens of the wetland lycopsid Sigillaria (figure 5.8). These 
are most likely S. brardii, effectively the only species of 
Sigillaria in the Late Pennsylvanian and Permian. Pfeffer-
korn and Wang (2009) demonstrated that the deeper roots 
of S. brardii allowed this species to tolerate drought better 
than the other giant lycopsids.
Also identified from Valley of the Gods are a few 
specimens of walchian conifers (figure 5.9). All poorly pre-
served, these specimens came from fissile, planar-laminat-
ed sandstone that occupied broad, shallow troughs within a 
channel (figure 5.2). Such occurrences indicate that walchi-
ans were present on the landscape, probably in interfluves 
where moisture deficits would be most strongly amplified 
under a prevailing, background seasonally dry climate re-
gime.
In addition to actual fossils, sedimentary features 
at Valley of the Gods suggest widespread plant coloniza-
tion of the landscape. For example, a flaggy siltstone bed 
near Setting Hen Butte contains more than 100 vertical, 
cylindrical features that penetrate the entire 15 centimeter 
thickness of the bed. Consistently about 4 centimeters in 
diameter, these cylinders have haloes of gray against the 
red background, suggesting chemical reduction caused by 
organic matter (figure7). Although these might be roots, 
their random spacing and lack of dense clumps (as might 
be expected from roots emanating from a stem base), to-
gether with occurrence of a paleosol directly below, sug-
gests that the cylinders represent small, upright stems that 
were partially buried in sediment. DiMichele and others 
(2012) described similar features (attributed to the prob-
able peltasperm, Supaia) from the lower Permian Abo For-
mation of New Mexico.
Indian Creek
The twelve small collections made along Indian 
Creek consist of two principal components, marattialean 
tree-fern foliage and stems of sphenophyllalean sphenop-
sids. The tree-fern foliage (figs. 6.5-6.7) is both vegetative 
(Pecopteris) and fertile (Asterotheca). No species deter-
minations could be made with confidence, on the basis of 
the specimens preserved. Tree ferns are common elements 
of wetland floras from both peat and mineral substrates. 
They produced large numbers of small, highly dispers-
ible spores, giving them prodigious colonization abilities. 
As a consequence, they were elements of many different 
kinds of landscapes, as long as there were wet substrate 
areas present that could be reached by their wind-dispersed 
spores.
One of the channel scours also contains abundant, 
silicified coniferophyte logs (Stanesco and others, 2002). 
These logs appear to have been transported and may rep-
resent a “log jam”, such as those reported from older rocks 
in the eastern U.S. and Canada (e.g. Gastaldo and Degges, 
2007; Gibling and others, 2010). The conifer Walchia also 
was found in sandstone from beds at this stratigraphic level.
DISCUSSION
Pennsylvanian-Permian boundary floras from the San 
Juan County, Utah region are few in number but signifi-
cant indicators of vegetation in western equatorial Pangea. 
The region was strongly influenced by winds off the Pan-
thalassa Ocean to the west, as well as by periodic climatic 
and sea-level changes induced by Southern Hemisphere, 
high latitude glaciation (reviewed in Tabor and Poulsen, 
2008; see also Soreghan and others, 2002; Montañez and 
others, 2007). In general, floras discussed herein are con-
sistent with a long-recognized trend toward increasing 
tropical aridity throughout the entire Euramerican region, 
within which there were shorter episodes of wetter climate, 
perhaps less than 1-3 million years in duration (Tabor and 
Poulsen, 2008).
A wetter episode (at least dry sub-humid) proposed 
to occur near the Pennsylvanian-Permian boundary in the 
Colorado Plateau (Soreghan and others, 2002) is consistent 
with the floras we describe in this paper. This period of in-
creased moisture may be associated with cycles of glacia-
tion at high elevations within the Ancestral Rocky Moun-
tains, in the Uncompahgre highlands (Soreghan and others, 
2008), fueled by a combination of cold temperatures and 
periodic increases in moisture delivery to the area. If cy-
cles of mountain glaciation occurred across the Pennsylva-
nian-Permian boundary in the Ancestral Rockies, and we 
acknowledge that such proposals are controversial, they 
could account for the periodic occurrence of wetland flo-
ras—or of any kind of floras—intercalated with intervals 
of extreme aridity. The close spatial physical proximity 
of sand dunes and flood-plain soils and channels, such as 
at Indian Creek (Stanesco and Campbell, 1989), may not 
necessarily be indicative of contemporaneity. Rather, the 
paleosols and channels preserving wetland plants might 
more likely represent periods of perennial to intermittent 
stream flow, accompanied by channel incision into, and 
floodplain development on, landscapes of stabilized dune 
fields during wet, cold, glacial intervals. The dunes may 
have become active again during warmer, arid interglacial 
intervals. Under such depositional conditions, bounding 
surfaces within the eolian deposits would mark periods 
of stabilization, caused either by rising water tables or in-
creased precipitation.
Pennsylvanian-Permian boundary floras from New 
Mexico (Tidwell and others 1999; DiMichele and others, 
2004; DiMichele and Chaney, 2005; DiMichele and others, 
2010) and Utah (Mamay and Breed, 1970; Tidwell, 1988) 
are similar to those reported here, and reveal a mix of plants 
typical of both wetlands and dry substrates. Such floras do 
not require widespread wet climates. Rather, they suggest 
that the prevailing climate was one of seasonal, locally se-
vere, drought, within which there were wet areas capable 
of supporting certain kinds of wetland plants, particularly 
those with high dispersal capabilities and capacities to tol-
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Figure 7.  Valley of the Gods, near Setting Hen Butte. 1. Siltstone surface covered with areas of iron reduction. 2. Detail of reduced area 
illustrating central core and root-like features surrounding the core area. Scale = 10 centimeters. 3. Pair of reduced areas showing similar-
ity of basic structure. Scale = 10 centimeters. 4. Paleosol below the siltstone bed illustrated in (7.1).
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erate short moisture deficits. The most likely scenario is 
that a number of perennial streams, sourced in the Uncom-
pahgre highlands, coursed across the coastal plain of the 
former Paradox Basin en route to the western ocean. At 
some intervals, perhaps during periods of mountain glacia-
tion as discussed above, these riverine corridors sustained 
large populations of plants adapted to wetter environments. 
Thus, at Valley of the Gods and Lime Ridge, we find 
fossils of large plants that represent all the major groups 
of Pennsylvanian wetland plants: tree ferns, calamitaleans, 
pteridosperms and lycopsids. The lycopsids and pteri-
dosperms are of particular note because they had large dis-
persal organs (megaspores for Sigillaria and large seeds in 
the case of the pteridosperms) that could not be broadcast 
widely. This observation implies either permanent western 
refugial areas for these plants during drought, or rapid ex-
pansion of their populations along continuously developed 
wetland corridors during short intervals of widespread wet-
ness. Tree ferns and calamitaleans could grow in margin-
ally wet areas, giving them the capacity to reach remote or 
isolated sites with wet soils. The former produced billions 
of small, highly dispersible spores, which could reach re-
mote wet areas. The latter included many streamside and 
lake margin specialists, which could recover from repeated 
disturbances (e.g., Gastaldo, 1992), and thus occupy small, 
but interconnected corridors with intermittent wetness. As 
noted above, perennial stream flow in fluvial systems may 
have, at times, been maintained by ice melting in the An-
cestral Rocky Mountains, which provided wetland condi-
tions in an otherwise dry, perhaps arid climate.
Plants reflecting seasonally dry conditions have been 
reported in floras from the Colorado Plateau from strata as 
old as Early Pennsylvanian (Tidwell, 1967). Such plants 
also occur in Pennsylvanian collections from the Midwest-
ern coal fields (Feldman and others, 2005; Falcon-Lang and 
others, 2009) but only in small channels that show evidence 
of seasonally dry conditions, developed between periods 
of coal formation. Their presence in our Utah collections 
thus is hardly surprising. In fact, such plants probably are 
greatly under-represented in the fossil record relative to 
their original dominance of the landscape during the dry 
phases of glacial-interglacial cycles, when conditions for 
organic preservation were least favorable (Gastaldo and 
Demko, 2011). 
Trunks of large conifers or cordaitaleans, such as those 
found at Indian Creek, have been reported elsewhere in the 
Colorado plateau from rocks of similar age (Condon, 1997; 
Stanesco and others, 2002). These occurrences suggest that 
stands of such trees flourished on the Uncompahgre high-
lands, where they may have received orographic rainfall, 
perhaps during all parts of glacial-interglacial cycles. These 
trees may then have spread along permanent streams into 
the lowlands during episodes of wetter climate. 
As a final note, plants from western Pangea are closely 
allied phylogenetically to groups that occur throughout the 
equatorial region. This is true both of the wetland and sea-
sonally dry taxa. Although the number of dominant class-
level groups, represented by distinct architectures, was 
more numerous than is typical of modern vegetation, the 
late Paleozoic tropics nonetheless hosted significantly few-
er species, genera, and families than do the modern trop-
ics. In a late Paleozoic world with far lower diversity than 
today, many individual species, therefore, may have had 
greater niche breadth than is typical among modern plants. 
Such resource breadth may have, perhaps to a consider-
able extent, buffered their populations from environmen-
tal changes. Most species had either wind dispersed pollen 
or spores, which would have contributed to high levels of 
gene flow and made possible large effective population siz-
es—these factors may have been among the most important 
responsible for the lower numbers of species. There are few 
tests of such hypotheses (but see Raymond and Costanza, 
2007), and clearly the late Paleozoic, and the western areas 
of Pangea, promise to be fertile areas for study of plant evo-
lutionary and ecological dynamics.
ACKNOWLEDGMENTS
We thank Jack Stanesco and Jackie Huntoon for in-
troducing us to many of the fossil deposits reported here. 
Gary Gianniny, Dave Berman, and Amy Henrici contrib-
uted materially to our understanding of the geology. Arden 
Bashforth and Stan Opluštil provided helpful, constructive 
reviews of an earlier version of this paper. The assistance 
of the Bureau of Land Management is gratefully acknowl-
edged. The Small Grants Program of the National Museum 
of Natural History supported this research.
REFERENCES
Baars, D.L., 1962, Permian System of Colorado Plateau: Ameri-
can Association of Petroleum Geologists Bulletin, v. 46, p. 
149-218. 
Baars, D.L., 1991, The Elephant Canyon Formation, for the last 
time: The Mountain Geologist, v. 28, p. 1-2. 
Baars, D.L., and Stevenson, G.L., 1981, Tectonic evolution of 
the Paradox basin, Utah and Colorado, in Wengerd, D.L., 
editor, Geology of the Paradox Basin: Rocky Mountain As-
sociation of Geologists, p. 23-31. 
Baker, A.A., and Reeside, J.B., Jr., 1929, Correlation of the Per-
mian of southern Utah, northern Arizona, northwestern 
New Mexico, and southwestern Colorado: American As-
sociation of Petroleum Geologists Bulletin, v. 13, p. 1413-
1448. 
Barbeau, D.L., 2003, A flexural model for the Paradox Basin: 
implications for the tectonics of the Ancestral Rocky 
Mountains: Basin Research, v. 15, p. 97-115.
Barthel, M., and Rößler, R., 1996, Palaeontologische Funds-
chichten in Rotliegend von Manebach (Thüringer Wald) 
mit Calamites gigas (Sphenophyta): Veröffentlichungen 
Naturhistorisches Museum Schleusingen 11, p. 3–21.
F
O
S
S
IL
 F
L
O
R
A
S
 F
R
O
M
 T
H
E
 P
E
N
N
S
Y
LV
A
N
IA
N
-P
E
R
M
IA
N
 C
U
T
L
E
R
 G
R
O
U
P 
O
F
 S
O
U
T
H
E
A
S
T
E
R
N
 U
TA
H
 –
 D
iM
ic
he
le
, W
.A
., 
C
ec
il
, C
.B
., 
C
ha
ne
y,
 D
.S
., 
E
lr
ic
k,
 S
.D
., 
an
d 
N
el
so
m
, W
.J
.
UGA Publication 43 (2014)—Geology of Utah's Far South502
Bashforth, A.R., Cleal, C.J., Gibling, M.R., Falcon-Lang, H.J., 
and Miller, R.F., 2014, Paleoecology of Early Pennsylvani-
an vegetation on a seasonally dry tropical landscape (Tyne-
mouth Creek Formation, New Brunswick, Canada): Re-
view of Palaeobotany and Palynology, v. 200, p. 229–263.
Blake, B.M., Jr., and Gillespie, W.H., 2011, The enigmatic 
Dunkard macroflora, in Harper, J., editor, Geology of the 
Pennsylvanian-Permian in the Dunkard basin: 76th Annual 
Field Conference of Pennsylvania Geologists Guidebook, 
p. 103-143.
Blake, B.M., Jr., Cross, A.T., Eble, C.F., Gillespie, W.H., and Pf-
efferkorn. H.W., 2002, Selected plant megafossils from the 
Appalachian region, eastern United States: geographic and 
stratigraphic distribution, in Hills, L.V., Henderson, C.M., 
and Bamber, E.W., editors, Carboniferous and Permian 
of the World: Canadian Society of Petroleum Geologists 
Memoir 19, p. 259–335.
Chaney, D.S., Lucas, S.G., and Elrick, S., 2013, New occurrence 
of an arthropleurid trackway from the Lower Permian of 
Utah: New Mexico Museum of Natural History and Sci-
ence Bulletin 60, p. 64-65.
Cecil, C.B., 1990, Paleoclimate controls on stratigraphic repeti-
tion of chemical and siliciclastic rocks: Geology, v. 18, p. 
533-536.
Cecil, C.B., and Dulong, F.T., 2003, Precipitation models for sed-
iment supply in warm climates, in Cecil, C.B., and Edgar, 
N.T., editors, Climate Controls on Stratigraphy: SEPM (So-
ciety for Sedimentary Geology) Special Publication 77, p. 
21-28.
Condon, S.M., 1997, Geology of the Pennsylvanian and Permian 
Cutler Group and Permian Kaibab Limestone in the Para-
dox basin, southeastern Utah and southwestern Colorado: 
U.S. Geological Survey Bulletin 2000-P, p. P1-P46.
DiMichele, W.A., and Chaney, D.S., 2005, Pennsylvanian-Per-
mian fossil floras from the Cutler Group, Cañon del Cobre 
and Arroyo del Agua areas, in northern New Mexico: New 
Mexico Museum of Natural History and Science Bulletin 
31, p. 26-33.
DiMichele, W.A., Kerp, H., and Chaney D.S., 2004, Tropical 
floras of the Late Pennsylvanian-Early Permian transition: 
Carrizo Arroyo in context: New Mexico Museum of Natu-
ral History and Science Bulletin 25, p. 105-109.
DiMichele, W. A., Tabor, N. J., Chaney, D. S., and Nelson, W. J., 
2006, From wetlands to wet spots: Environmental tracking 
and the fate of Carboniferous elements in Early Permian 
tropical floras: Geological Society of America Special Pa-
per 399, p. 223-248.
DiMichele, W.A., Chaney D.S., Kerp, H., and Lucas, S.G., 2010, 
Late Pennsylvanian floras in western equatorial Pangea, 
Cañon del Cobre, New Mexico: New Mexico Museum of 
Natural History and Science Bulletin 49, p. 75-113.
DiMichele, W.A., Lucas, S.G., and Krainer, K., 2012, Vertebrate 
trackways among a stand of Supaia White plants on an 
Early Permian floodplain, New Mexico: Journal of Paleon-
tology, v. 86, p. 584-594.
Dubiel, R.F., Huntoon, J.E., Condon, S.M., and Stanesco, J.D., 
1996, Permian deposystems, paleogeography, and paleocli-
mate of the Paradox basin and vicinity, in Longman, M.W., 
and Sonnenfeld, M.D., editors, Paleozoic Systems of the 
Rocky Mountain Region: SEPM (Society for Sedimentary 
Geology) Rocky Mountain Section, p. 427-444. 
Dubois, M.K., Goldstein, R.H., and Hasiotis, S.M., 2012, Cli-
mate-controlled aggradation and cyclicity of continental 
loessic siliciclastic sediments in Asselian–Sakmarian cy-
clothems, Permian, Hugoton embayment, U.S.A: Sedimen-
tology, v. 59, p. 1782-1816.
Falcon-Lang, H.J., and Bashforth, A.R., 2005, Morphology, 
anatomy, and upland ecology of large cordaitalean trees 
from the Middle Pennsylvanian of Newfoundland: Review 
of Palaeobotany and Palynology, v. 135, p. 223-243.
Falcon-Lang, H.J., Nelson, W.J., Elrick, S., Looy, C.V., Ames, 
P.R., and DiMichele, W.A., 2009, Incised channel fills con-
taining conifers indicate that seasonally dry vegetation 
dominated Pennsylvanian tropical lowlands: Geology, v. 
37, p. 923-926.
Feldman, H.R., Franseen, E.K., Joeckel, R.M., and Heckel, P.H., 
2005, Impact of longer-term modest climate shifts on archi-
tecture of high-frequency sequences (cyclothems), Penn-
sylvanian of Midcontinent U.S.A: Journal of Sedimentary 
Research, v. 75, p. 350-368.
Gastaldo, R.A., 1992, Regenerative growth in fossil horsetails 
following burial by alluvium: Historical Biology, v. 6, p. 
203-219.
Gastaldo, R.A., and Degges, C.W., 2007, Sedimentology and 
paleontology of a Carboniferous log jam: International 
Journal of Coal Geology, v. 69, p. 103-118.
Gastaldo, R.A., and Demko, T.M., 2011, The relationship be-
tween continental landscape evolution and the plant-fossil 
record: Long term hydrologic controls on preservation, in 
Allison, P.A., and Bottjer, D.J., editors, Taphonomy: Proc-
ess and bias through time: Topics in Geobiology, v. 32, p. 
249-285.
Gibling, M.R., Bashforth, A.R., Falcon-Lang, H.J., Allen, J.P., 
and Fielding, C.R., 2010, Log jams and flood sediment 
buildup caused channel abandonment and avulsion in the 
Pennsylvanian of Atlantic Canada: Journal of Sedimentary 
Research, v. 80, p. 268-287.
Hilton, J., and Cleal, C.J., 2007, The relationship between Eura-
merican and Cathaysian tropical floras in the Late Palaeo-
zoic: Palaeobiogeographical and palaeogeographical impli-
cations: Earth-Science Reviews, v. 85, p. 85-116.
Hunt, A.P., and Lucas, S.G., 1992, The paleoflora of the lower 
Cutler Formation (Pennsylvanian: Desmoinesian?) in El 
Cobre Canyon, New Mexico and its biochronological sig-
nificance: New Mexico Geological Society, 43rd Annual 
Field Conference, p. 145-150.
Huntoon, P.W., Billingsley, G.H., Jr., and Breed, W.J., 1982, 
Geologic map of Canyonlands National Park and vicinity, 
Utah: Moab, Canyonlands Natural History Association, 1 
sheet, scale 1:62,500. 
Huntoon, J.E., Dubiel, R.F., Stanesco, J.D., Mickelson, D.L., and 
Condon, S.M., 2002, Permian-Triassic depositional sys-
tems, paleogeography, paleoclimate, and hydrocarbon re-
sources in Canyonlands and Monument Valley, Utah: Geo-
logical Society of America Field Guides 2002, v. 3, p. 33-58.
Jordan, O.D., and Mountney, N.P., 2012, Sequence stratigraphic 
MacLean, J.S., Biek, R.F., and Huntoon, J.E., editors
F
O
S
S
IL
 F
L
O
R
A
S
 F
R
O
M
 T
H
E
 P
E
N
N
S
Y
LV
A
N
IA
N
-P
E
R
M
IA
N
 C
U
T
L
E
R
 G
R
O
U
P O
F
 S
O
U
T
H
E
A
S
T
E
R
N
 U
TA
H
 – D
iM
ichele, W
.A
., C
ecil, C
.B
., C
haney, D
.S., E
lrick, S.D
., and N
elsom
, W
.J.
503
evolution and cyclicity of an ancient coastal desert system: 
The Pennsylvanian-Permian lower Cutler beds, Paradox 
Basin, Utah: Journal of Sedimentary Research, v. 82, p. 
755-780.
Kerp, J.H.F., and Fichter, J., 1985, Die Makrofloren des saarp-
fälzischen Rotliegenden (?Ober-Karbon-Unter-Perm; SW 
Deutschland): Mainzer geowissenschaftliche Mitteilungen 
14, p. 159-286.
Langford, R.P., Pearson, K.M., Duncan, K.A., Tatum, D.M., 
Adams, L., and Depret, P.-A., 2008, Eolian topography as 
a control on deposition incorporating lessons from mod-
ern dune seas: Permian Cedar Mesa Sandstone, S.E. Utah, 
U.S.A.: Journal of Sedimentary Research, v. 78, p. 410-422.
Loope, D.B., Sanderson, G.A., and Verville, G.J., 1990, Aban-
donment of the name “Elephant Canyon Formation” in 
southeastern Utah; physical and temporal implications: 
The Mountain Geologist, v. 27, p. 119-130. 
Lupia, R., and Armitage, J.L., 2013, Late Pennsylvanian-Early 
Permian vegetational transition in Oklahoma: Palynologi-
cal record: International Journal of Coal Geology, v. 119, 
p. 165-176. 
Mamay, S.H., and Breed, W.J., 1970, Early Permian plants from 
the Cutler Formation in Monument Valley, Utah: U.S. Geo-
logical Survey Professional Paper 700, p. 109-117.
Montañez, I.P., Tabor, N.J., Niemeier, D., DiMichele, W.A., 
Frank, T.D., Fielding, C.R., Isbell, J.L., Birgenheier, L.P., 
and Rygel, M.C., 2007, CO2-forced climate and vegetation 
instability during late Paleozoic deglaciation: Science, v. 
315, p. 87-91.
Naugolnykh, S.V., 2005, Permian Calamites gigas Brongniart, 
1828: The morphological concept, paleoecology, and im-
plications for paleophytogeography and paleoclimatology: 
Paleontological Journal, v. 39, p. 321-332.
Opluštil, S., Pšenicˇ  ka, J., Libertín, M., Bashforth, A.R., and Šimu˚  
nek, Z., 2009, A Middle Pennsylvanian (Bolsovian) peat-
forming forest preserved in situ in volcanic ash of the 
Whetstone Horizon in the Radnice Basin, Czech Republic: 
Review of Palaeobotany and Palynology, v. 155, p. 234-274. 
Opluštil, S., Šimu˚   nek, Z., Zajíc, J., and Mencl, V., 2013, Clim-
atic and biotic changes around the Carboniferous/Permian 
boundary recorded in the continental basins of the Czech 
Republic: International Journal of Coal Geology, v. 119, p. 
114-151. 
O’Sullivan, R.B., 1965, Geology of the Cedar Mesa-Boundary 
Butte area, San Juan County, Utah: U.S. Geological Survey 
Bulletin 1186, p. 1-128 and map, scale 1:62,500. 
Pfefferkorn, H.W., and Wang, J., 2009, Stigmariopsis, Stigmaria 
asiatica, and the survival of the Sigillaria brardii-ichthy-
olepis group in the tropics of the late Pennsylvanian and 
Early Permian: Palaeoworld, v. 18, p. 130-135.
Raymond, A., and Costanza, S., 2007, Are wind-pollinated 
plants less diverse and longer ranging than insect-pollinat-
ed groups? [abs.]: Geological Society of America Abstracts 
with Programs, v. 39, no. 6, p. 565.
Raymond, A., Lambert, L., Costanza, S., Slone, E.J., and Cutlip, 
P.C., 2010, Cordaiteans in paleotropical wetlands: An eco-
logical re-evaluation: International Journal of Coal Geol-
ogy, v. 83, p. 248-265.
Roscher, M., and Schneider, J.W., 2006, Permo-Carboniferous 
climate: Early Pennsylvanian to Late Permian climate 
development of central Europe in a regional and global 
context, in Lucas, S.G., Cassinis, G., and Schneider, J.W., 
editors, Non-marine Permian biostratigraphy and bio-
chronology: Geological Society of London Special Publi-
cation 265, p. 95-136.
Rößler, R., and Noll, R., 2006, Sphenopsids of the Permian (I): The 
largest known anatomically preserved calamite, an excep-
tional find from the petrified forest of Chemnitz, Germany: 
Review of Palaeobotany and Palynology, v. 140, p. 145-162.
Sanderson, G.A., and Verville, G.J., 1990, Fusulinid zonation 
of the General Petroleum No. 45-5-G core, Emery County, 
Utah: The Mountain Geologist, v. 27, p. 131-136. 
Soreghan, G.S., Elmore, R.D., and Lewchuk, M.T., 2002, Sed-
imentologic-magnetic record of western Pangean climate 
in upper Paleozoic loessite (lower Cutler beds, Utah): Geo-
logical Society of America Bulletin, v. 114, p. 1019-1035.
Soreghan, G.S., Soreghan, M.J., Poulsen, C.J., Young, R.A., Eble, 
C.F., Sweet, D.E., and Davogustto, O.C., 2008, Anomalous 
cold in the Pangaean tropics: Geology, v. 36, p. 659-662. 
Stanesco, J.D., and Campbell, J.A., 1989, Eolian and noneolian 
facies of the Lower Permian Cedar Mesa Sandstone Mem-
ber of the Cutler Formation, Southeastern Utah: U.S. Geo-
logical Survey Bulletin 1808-F, p. F1-F13.
Stanesco, J.D., Huntoon, J.E., and Mickelson, D.L., 2002, Geo-
logic setting of a Permian plant and vertebrate site, south-
eastern Utah [abs.]: Geological Society of America 2002 
Annual Meeting Abstract 222-6.
Sur, S., Soreghan, G.S., Soreghan, M.J., Yang, W., and Saller, 
A.H., 2010, A record of glacial aridity and Milankovitch-
scale fluctuations in atmospheric dust from the Pennsyl-
vanian tropics: Journal of Sedimentary Research, v. 80, p. 
1046-1067.
Tabor, N.J., and Poulsen, C.J., 2008, Palaeoclimate across the 
Late Pennsylvanian–Early Permian tropical palaeolati-
tudes: A review of climate indicators, their distribution, 
and relation to palaeophysiographic climate factors: Pal-
aeogeography, Palaeoclimatology, Palaeoecology, v. 268, 
p. 293-310.
Tabor, N.J., DiMichele, W.A., Montañez, I.P., and Chaney, D.S., 
2013, Late Paleozoic continental warming of a cold tropical 
basin and floristic change in western Pangea: International 
Journal of Coal Geology, v. 119, p. 177-186. 
Tidwell, W.D., 1967, Flora of the Manning Canyon Shale, Part I: 
A lowermost Pennsylvanian flora from the Manning Can-
yon Shale, Utah, and its stratigraphic significance: Brigham 
Young University Geology Studies, v. 14, p. 3-66.
Tidwell, W.D., 1988, A new Upper Pennsylvanian or Lower Per-
mian flora from southeastern Utah: Brigham Young Uni-
versity Geology Studies, v. 35, p. 33-56.
Tidwell, W.D., Ash, S.R., Kues, B.S., Kietzke, K.K., and Lucas, 
S.G., 1999, Early Permian megafossils from Carrizo Ar-
royo, Central New Mexico: New Mexico Geological Soci-
ety Guidebook 50, p. 297-304.
Vaughn, P.P., 1962, Vertebrates from the Halgaito Tongue of 
the Cutler Formation, Permian of San Juan County, Utah: 
Journal of Paleontology, v. 36, p. 529-539. 
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.A
., 
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, C
.B
., 
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y,
 D
.S
., 
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lr
ic
k,
 S
.D
., 
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d 
N
el
so
m
, W
.J
.
UGA Publication 43 (2014)—Geology of Utah's Far South504
Wagner, R.H., and Álvarez-Vázquez, C., 2010, The Carbonifer-
ous floras of the Iberian Peninsula: A synthesis with geo-
logical connotations: Review of Palaeobotany and Palynol-
ogy, v. 162, p. 239-324.
Wang, J., and Pfefferkorn, H.W., 2013, The Carboniferous-Per-
mian transition on the North China microcontinent—Oce-
anic climate in the tropics: International Journal of Coal 
Geology, v. 119, p. 106-113.