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O, C. Marsh — Amphibian Footprints. 



Art. LY. — Amphibian Footprints from, the Devonian / 

 by O. C. Marsh. 



No evidence of vertebrate life higher than that of Fishes 

 has hitherto been found in the Devonian formation. In the 

 Carboniferous next above, however, many characteristic remains 

 of Amphibians have long been known, proving that this form 

 of vertebrate life was comparatively abundant at that period. 



The Yale Museum has recently secured from the upper 

 Devonian strata of western Pennsylvania, a specimen that 

 shows one vertebrate footprint in fair preservation, and with 

 it part of another of the same series. These impressions are 

 of much interest, both on account of their geological age and 

 the size and character of the footprints themselves. The one 

 best preserved is nearly four inches in length, two and a 

 quarter in width, and was apparently made by a left hind foot. 

 On the inner side in front of the heel, a portion of the margin 

 is split off, and this may have contained the imprint of another 

 toe. The other footprint was a short distance in front, but 

 only the posterior portion is now preserved in the present 

 specimen. It is probably the imprint of the fore foot. The 

 figure shown below represents these two impressions. 



Outline of Devonian footprints (Thinopus antiquus, Marsh). 

 One-half natural size. 



The specimen here figured was recently found in the town 

 of Pleasant, one mile south of the Allegheny River, Warren 

 County, Pennsylvania, by Dr. Charles E. Beecher, who pre- 

 sented it to the Yale Museum, and also furnished the present 

 information in regard to its geological position. 



The geological horizon is near the top of the Chemung, in 

 the upper Devonian. In the same beds are ripple marks, 

 mud cracks, and impressions of rain drops, indicating shallow 



