RECENTLY FOUND METEORIC IRONS FROM MESAVERDE PARK, COLO., AND SAVANNAH, TENN.
By George P. Merrill,Head Curator of Oeology, United States National Mnseum.
1. MESA VERDE PARK, COLO.'The iron described below was brought to the Museum by Dr.J. Walter Fewkes, Director of the Bureau of American Ethnology,on his return from a field inspection trip during the summer of1922. It was found, commingled with miscellaneous rock fragments,in the Sun Shrine at the north end of Pipe Shrine House in theMesa Verde National Park of Colorado. There was nothing in itsposition or surroundings to indicate that the aborigines by whom itwas placed realized its ultra terrestrial origin or regarded it withother or more interest than was attached to the fragments of softsandstone and other rock debris with which it was associated.As found, the iron?in the position indicated in the plate?stood 16cm. in height by 10 cm. in breadth and 8 cm. in maximum thicknessand weighed when cleaned 3.52 kilograms. It was considerablyoxidized and manj^ of the depressions partially filled with the oxida-tion products. The characteristic thumb marks or depressions arestill in evidence, sufficiently plain to enable one to pronounce at onceupon its meteoric nature. There are no broken surfaces, and evi-dently it represents a " complete individual.'" An etched surface(pi. 1, fig. 3) shows it to be a medium octahedrite of ordinary type.The kamacite bands are slightly swollen and plessite areas are propor-tionally abundant. Schreibersite and taenite are quite inconspicuousexcept under a glass. No secondary granulation (metabolism) is rec-ognizable. Doctor Fewkes says that the position of the find was suclias to indicate with a fair degree of certainty that it was placed thereduring the period of construction, and therefore that the time of fallcan not be later than the thirteenth century, the date conunonlyassigned to these ruins.
1 Mutieum Catalogue, No. 645.No. 2487-Proceedings U. S. National Musium. Vol. 63. Art. 18 1
2 PROCEEDINGS OP^ THE NATIONAL MUSEUM. vol.63.It would seem strange that the iron had not excited more than pass-ing notice by the native builders, but, as stated, there is nothing toindicate that it received other attention than that given to the Cre-taceous fossiliferous limestone and sandstone fragments with whichit was commingled. There is, however, a singular lack of evidence toshow that the early American, even down to the modern Indian, real-ized the possible uses of metal, although quick to discriminate in thecharacter of stone selected from which to make his weapons or ar-ticles for domestic use. The writer has elsewhere ^ called attentionto the abundant small, sharp-edged thin flakes of meteoric iron foundlying on the surface in the vicinit}' of the Canon Diablo crater. Manyof these w^ould seem to have been admirably adapted even in theirnatural condition to cutting and scraping purposes or even toweapons, but thus far there has not been put on record a single caseof such usage. That the fall was an ancient one is beyond question,yet through all the hundreds of subsequent years the material hasbeen ignored, if not wholly overlooked.
2. SAVANNAH, HARDIN COUNTY, TENN/The meteoric iron figured and described in the following pageswas brought to my attention by Prof. Wilbur A. Nelson, Stategeologist of Tennessee, who I'eports that it was found by Messrs.C. D. Wright and M. W. Spencer while working on the road formingthe main highway between Savannah and Cerro Gordo in HardinCounty and some 4 miles northeast of tlie first-named town. Themass was brought to the survey office of the State geologist under thesupposition that it was an iron ore, and there identified. In theautumn of the present year it was sent to the National Museum, whereit has been cut along its greatest diameter and etched and portionssubmitted for analysis with results given below.As found the iron is in form of a rough, somewhat flattened, dumb-bell-shaped mass (see pi. 2) greatl}' oxidized on the exterior surface.Its maximum dimensions were 143.5 by 25.5 by 16.5 cm. and itsweight some 60 kilograms (135 pounds). Neither dimensions norweight can be given accurately', as small fragments of oxidized mate-rial Avere continuall}' scaling away.An etched surface shows the iron to be, with the exception notedlater, a normal coarse ochtahedrite but much pitted by oxidation,which has so deeply penetrated the mass as to greatly weaken it andrender it liable to fracture through the middle or most constrictedportion. The kamacite bands are quite variable, being at times of
" Contributions to the Study of the Canon Diablo Meteorite, Smithsonian Misc. Coll..vol. 50, pt. 2. 1907. Note particularly pi. 21."Museum Cataroguo, No. 706.
AKT. 18. SOME RECENTLY FOUND METEORIC IRONS MERRILL. 3uniform thickness throughout or again swollen, as is shown in theplate. Plessite areas are abundant and large, varying in size up to10 mm. in diameter. No troilite nodules are visible on the cut sur-face, and no schreibersite. The taenite is visible on the etched sur-face only in the usual disconnected thin films.The striking feature of the iron lies in the varied orientation of thecrystal plates in the center and two end portions of the mass (see pis.2 and 3). It will be noted that in this central portion {D) the kama-cite plates are for the most part thin, closely crowded, and lie nearlyhorizontally (in the figure). To the left they become separated andthe structure becomes more nearly that of a normal octahedrite. Onthe right, however, along the somewhat wavy line A-B^ they abutagainst a single disconnected row of plates extending nearly verticaland are no longer continuous throughout the remaining portion ofthe mass to the right. Nor are the vertical and diagonal plates Cand E in the two portions quite parallel with one another, and thereis a slight difi'erence in manner of etching and in the relative thick-ness of the kamacite bands in the two portions. This last is mostplainly noticeable in the lower part of plate 3. What portion ofthese differences may be due to the angle of cutting, the Avriter isnot at present prepared to say; the appearance is certainly such asto suggest the welding of two quite similar irons along this linerather than twinning after the manner of the Mukerop, as is de-scribed by Berwerth.Chemical analysis by Whitfield yielded
:
Per cent.Iron 83. 621Nickel 7. 762Cobalt . 333Phosphorus ? 130Sulphur .0.'>8Chlorine ? 107Carbon . 475Silicon None.Manganese None.Copper yow.
^Metallic oxides ?'?? ^^^Water 1- 290Insoluble ? 346100. 017The 5.895 per cent metallic oxides yielded ferric oxide (Fe,0,),4.995 per cent; nickel and cobalt oxides (XiO-CoO), 0.9-i per cent.The 0.346 per cent insoluble yielded 0.242 per cent iron. A " direct "determination gave 87.802 per cent total iron. This is a little belowthe average for a coarse octahedrite, though, as usual, this is com-
4 PROCEEDIISrGS OF THE NATIONAL MUSEUM. vol. 63, art. 13pensated for by a correspondingly high content of nickel, as ex-emplified also in the irons of Bendego, Canyon City, and Magura.Otherwise the results seem in no way worthy of remark, unless theabsence of copper and tin should be so considered.EXPLANATION OF PLATES.Plate 1.Figs. 1 and 2.?Mesa Verde iron in reversed positions. Fig. 3.?Etchedsurface of portion of Mesa Verde iron,Plate 2.Etclied surface of Savannah meteoric iron ; full-length section.Plate 3.Etched surface central portion of Savannah nieteorite enlargecL
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