82 O. C. Marsh — Footprints in the Coal Measures. 



With these impressions were still others, made either by 

 animals nearly allied or by the same animals under different 

 circumstances. These need not be further noticed in this con- 

 nection, but they serve to emphasize the diversity of life at 

 this point. The typical series are briefly described below. 



JSFanopus caudatus, gen. et sp. nov. 



The first series represented on Plate II, figure 1, indicates 

 the smallest animal that here left a distinct series of footsteps, 

 and the only one in which an imprint made by the tail was 

 preserved. This small quadruped had evidently but three 

 functional toes on the fore feet and four on those behind. 

 The fore feet were considerably smaller than the hind feet. 

 The impressions made by the latter are nearly all separate 

 from the anterior footprints, although at times slightly over- 

 lapping them. One fore and one hind footprint of this series 

 are represented, natural size, on Plate III, figure 1. 



The nature of the animal indicated by these impressions can 

 at present be a matter of conjecture only, but the probabilities 

 are in favor of its reference to the Amphibians rather than to 

 the true Rejptilia. As it is evidently distinct from anything 

 hitherto described, the above name is proposed for it. 



Limnojpus vagus, gen. et sp. nov. 



In figure 2, Plate II, a second series of footprints is repre- 

 sented, somewhat larger than those above described, and 

 evidently made by a very different animal. A fore and hind 

 footprint of this series are shown, natural size, in figure 2, Plate 

 III. The front feet had four functional toes, while those behind 

 had five, all well developed. The impressions of the hind feet, 

 as a rule, overlap those of the corresponding fore feet. No 

 indications of a tail can be detected. In length of stride, and 

 in the distance between the footsteps of the right and left 

 sides, the present series is proportionately about the same as 

 those above described, although the animals differed much in 

 size. They were probably both Amphibians, and may have 

 been nearly allied. 



Dromopus agilis, gen. et sp. nov. 



The third series of footprints shown on Plate II, figure 3, is 

 of special interest, and indicates an animal very distinct from 

 the two already described. On Plate III, figure 3, an outline 

 impression is given, natural size, of one double footmark of 

 this series, made by the fore and hind feet of the left side. 

 This diagram represents the impression of the phalanges 

 sufficiently in detail to indicate their number and general form. 

 A striking feature in the fore and hind feet of this animal was 



