452 J. B. WOODWORTII — VERTEBRATE FOOTPRINTS, PLAIN VI LLE 



On the opposite side of the .street occurs an outcrop of the vertical slate 

 series standing at a higher level than the nearly Hat beds exposed 30 feet 

 distant. The sandstones of the base of the block are very thickly beset 

 with joints as the result of the overthrusting of the block. 



Westward on that margin of the block beyond the limits of the sketch 

 map the gray Carboniferous rocks of the block abut against red beds 

 belonging near the base of the Carboniferous series, the relation being 

 effected by faulting. 



RAIN PRINT HORIZONS 



At several horizons on the eastern face of the Blake Hill fault-block 

 the shales have been observed to carry the impressions of rainprints, 

 showing that the mud beds were bared to the air, and that the entire 

 series was accumulated in shallow water if not in a fluvial or lacustrine 

 plain. This geographic feature suggested the search for the footprints 

 of Carboniferous amphibians — a search which was at once successful. 



Footprints 



description of the plainville tracks 



The footprints represent the tracks of two individuals, one set being 

 small and distinct, the other larger, but indicated by two imperfect im- 

 pressions only (see plate 40, figures 1 and 2). 



^5^ 



Figure 2.—Batrachichrws plainviltensis sp. now (y). 



The smaller tracks are those of a four-footed, tailed animal (see figure 

 2), with fairly distinct impressions of fore and hind feet. The fore feet 

 gave four-toed, the hind feet five-toed, impressions. The following 

 measurements are given to supplement the illustrations : 



Forefoot: length, 6.5 millimeters; breadth, 4 millimeters. 

 Hind foot: length, 11 millimeters; breadth, 5 millimeters. 

 Length of stride, left maims, 22 millimeters. 

 Breadth of tail-groove, 1.5 millimeters. 

 Breadth of track, 22 millimeters, 



