514 



SCIENCE 



[N. S. Vol. LI. No. 1325 



For dates in the Julian (Old Style) calen- 

 dar tlie formula is 



{Y + 4:C + L + M + D + 5)/7 = Q + E/7, 



in which the various symbols have the same 

 meanings as above. 



W. J. Spillman 



ORIGIN OF THE SUPPOSED HUMAN FOOT- 

 PRINTS OF CARSON CITY, NEVADA 



During the sunamer of 1919 the writer found 

 occasion to visit Carson City, Nevada, and, 

 through courtesy of members of the prison 

 staff at the Nevada State Penitentiary, was 

 enabled to examine a number of specimens of 

 fossil mammals collected in the prison yard 

 during past quarrying operations for building 

 stone. In the material preserved in the col- 

 lections were fragments of a skull and a cer- 

 vical vertebra belonging to a ground sloth. 

 Warden E. B. Henrichs, of the Nevada prison, 

 was kind enough to loan the remains recovered 

 during the excavations to the department of 

 paleontology. University of California, and 

 further study indicates that the ground sloth 

 specimens pertain to an individual of the genus 

 Mylodon. 



Many years ago the discovery of footprints, 

 bearing a superficial resemblance to imprints 

 made by a human foot, in a shale stratum ex- 

 posed in the yard of the x>enitentiary at Car- 

 son City, gave rise to the view that the exist- 

 ence of primeval man in Nevada was definitely 

 established — ^a view that has taken a particu- 

 larly tenacious hold. The possibility that the 

 footprints were in reality those of a ground 

 sloth, presumably of a form related to the 

 South American Mylodon, was, however, ad- 



vocated by Joseph Le Conte,^ 0. C. Marsh^ 

 and others. In 1917, the writer^ contrasted the 

 outline of the so-called human footprints with 

 that of a complete hind foot of Mylodon har- 

 lani reconstructed from remains of this species 

 secured in the asphalt deposits at Eancho La 

 Brea. The great resemblance which the artic- 

 ulated foot bore to the impressions, both in 

 outline and in size, seemed certain proof that 

 the latter were left by Mylodon. 



The actual occurrence of osseous remains of 

 Mylodon in the Pleistocene deposits at Carson 

 City, Nevada, removes still farther the possi- 

 bility that the Carson footprints are to be at- 

 tributed to a member of the Hominidse and 

 materially substantiates the suggestions of Le 

 Conte and Marsh. Further, the presence of 

 material referable to a mylodont sloth gives a 

 high degree of probability to the contention 

 that the footprints were made by Mylodon 

 rather than by some other quadruped. 



Chester Stock 



University op California 



SCIENTIFIC PHOTOGRAPHY 



To THE Editor of Science : The Eoyal Pho- 

 tographic Society of Great Britain is hold- 

 ing its sixty-fifth annual exhibition in Sep- 

 tember and October of this year. This is the 

 most representative exhibition of photographic 

 work in the world, and the section sent by 

 American scientific men heretofore has suffi- 

 ciently demonstrated the place held by this 

 country in applied photography. It is very 

 desirable that American scientific photography 

 should be equally well represented in 1920, 

 and, in order to enable this to be done with as 

 little difficulty as possible, I have arranged 

 to collect and forward American work in- 

 tended for the scientific section. 



This work should consist of prints showing 

 the use of photography for scientific purposes 

 and its application to spectroscopy, astronomy, 



1 Le Oonte, J., Proc. Calif. Acad. Sci., 10 pp., 

 August 27, 1882. 



2 Marsh, O. C, Amer. Jour. Sci., Ser. 3, Vol. 26, 

 pp. 139-140, 1883. 



3 Stock, C, Univ. Oalif. Publ. Bull. Dept. Geol., 

 Vol. 10, pp. 284-285, 1917. 



