104 THE UNIVERSITY SCIENCE BULLETIN. 



yet remains in situ, but will be removed in the spring. The first im- 

 pression in the series occurs at the mouth of the small ravine, where 

 it empties over the edge of the deeply undercut, rocky, shelving 

 bank into the Wakarusa. At this point the smooth, level bed of the 

 creek is composed of the same sandy formation (plate II) as that in 

 which the tracks appear. From the bed of the creek to the level of 

 the first track there is an elevation of fourteen feet. This track, like 

 several others in the set, shows the imprint of more than one foot. 

 It also shows plainly that the animal must have been of great size 

 and weight, for from the marks made by the claws (plate I, fig. 10) 

 of the front foot, at the extreme upper edge of the basinlike cavity 

 each impression has made, to the level of the superimposed im- 

 pression of the hind foot there is a depth of over fifteen inches. It 

 may be doubted if an animal of less than from 400 to 500 pounds 

 weight could possibly have left as deep an imprint as is here shown. 

 From the first track to the second, a distance of twelve feet, there is 

 an elevation of three feet. 



There is no doubt that the animal was well adapted for traveling 

 on land, as well as for life in the wet and swampy marshes, and that 

 its body was carried clear of the ground, requiring relatively long 

 limbs. The imprints also indicate that an upright position was 

 maintained, the toes of the feet being planted in a straight line 

 parallel to the body and to the line of travel. The footprints sug- 

 gest that the animal was of very robust build, possibly not unlike 

 that of Eryops from the Permian of Texas, but probably of longer 

 limb. It may well be that the form described herewith as 

 Onychopus gigas is a Carboniferous representative of this well- 

 known fossil amphibian, or some similar animal with a longer 

 length of limb. 



Onychopus gigas gen. et sp. nov. 



An entirely new form of amphibian is indicated by the present 

 series of footprints, for which the term Onychopus gigas is proposed. 

 The generic term refers to the presence of claws, apparently for both 

 fore and hind feet. Claws are known among previously described 

 Paleozoic vertebrates, particularly among the Permian reptiles, but 

 are here regarded as a generic character. Their presence is indi- 

 cated in the long, sharply marked grooves on the edges of the foot- 

 prints, where the sluggish animal lazily dragged his feet from the 

 soft sand. Another new character is an apparent presence of heel 

 pads (plate I, figs. 2-10), which are represented in the footprints as 

 depressions at the base of the footprint. Further discoveries may 



