Trof. 0. C. Marsh — Footprints in the Coal-measures. 339 



of the hind feet also left deep trails as they swung outward at each 

 step. On Plate XI. Figs 4 and 4a these two kinds of footprints 

 are represented. They show the stride of the animal, and, as put 

 together, also denote the width between the footprints of the two 

 sides, so that the series can be compared with the others on the same 

 plate. 



These tracks show that the animal had five toes in the fore feet 

 and four behind. The hind feet show a distinct impression of a sole. 

 There is no imprint of a tail, even where the mud appears to have 

 been deep. 



Baropus lentus. PI. XL Fig. 5. 



The most abundant of the large footprints are represented by 

 several series, which are remarkably uniform in stride and in width 

 between the right and left rows. One of these series is represented 

 on Plate XI. Fig. 5, and this is typical of the others. The animal 

 that made these footprints evidently had four functional toes in front 

 and the same number behind. On the inner side of each foot, 

 however, there was a projection, which, in the hind feet, was quite 

 prominent and characteristic, but can hardly be interpreted as the 

 imprint of the first digit. Nearly all these footprints show a distinct 

 impression of a sole. This is usually faint in the tracks of the fore 

 feet, but strongly marked in those behind. 



It is hardly necessary at this time to attempt a detailed com- 

 parison of the footprints above described with those already on 

 record. The present specimens all have well-marked characters, 

 and, being from a single horizon and locality, have a value of their 

 own as throwing light on the land vertebrate life, during the 

 deposition of the true Coal-measures. If, in themselves, they add 

 but little to what is already known, they at least offer encourage- 

 ment to investigators in an interesting field not yet systematically 

 explored. The publications of Logan, Lyell, King, Lea, Dawson, 

 and others have already made known discoveries of importance in 

 this country, and others have been recorded in the Old World. 



So far as at present known, land vertebrate life began in the 

 Carboniferous age, no footprints or other remains of this kind 

 having been detected below the sub-Carboniferous. That such 

 remains will eventually be found in the Devonian, there can be 

 no reasonable doubt, and perhaps even in the Silurian, if the land 

 surfaces then existing can be explored. 



EXPLANATION OF PLATE XI. 



EiG. 1. — Series of footprints of JVanopus candatus, Marsh ; showing, also, im- 

 pression made by the tail. 



,, 2. — Series of footprints of Limnopus vagus, Marsh. 



,, 3. — Series of footprints of Bromopus agilis, Marsh; showing trails made by 

 the toes. 



,, 4. — Two pairs of footprints of Allopus Uttoralis, Marsh; right side. 



,, 4a. — Footprints of same ; showing trails made by the toes ; left side. 



,, 5. — Series of footprints of Baropus lentus, Marsh. 



All the figures are one-twelfth natural size. 



