38 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



* 



The following description of the shales and footprints are from Dr. Branson's 

 paper cited above: 



"The Hinton shales, like the Mauch Chunk, seem to have been subaerial in origin and 

 are made up for the most part of variegated shales interbedded with thin layers of argil- 

 laceous, fine-grained sandstone. The footprints occur in fine-grained sandstone, and remains 

 of land plants are not uncommon in the same beds. 



' ' Twenty-two footprints made by one animal walking in a straight course were collected 

 in a slab. They give the impression of having been made by a bipedal animal for part of 

 the distance, but after the fourth print of the right foot impressions of the forefeet appear. 

 The hindfeet had 5 digits, the middle digit being longest and the 2 inside of it being only 

 slightly shorter and lying close together. Their outer ends were slender and flexible and 

 usually curved inward toward the middle toe. The 2 outer digits formed wide angles with 

 the middle one and were shorter than the inner ones. The second toe was webbed to within 

 8 mm. of the tip, the third toe to within 23 mm. of the tip. The impression of the web is 

 well preserved in only one impression of the hindfoot. 



"The forefeet had 4 digits. The 3 inner digits were subequal in length, the 2 inner 

 being more flexible and incurved near the ends. The outer digit is two-thirds as long as 

 the second. The webbing extends about half the length of the digits. The heel impression 

 is broader than that of the hindfoot. 



"Measurements of Dromopus aduncus Branson. 



Tip of toe to tip of toe in first prints 21 cm. 



After appearance of forefeet the impressions are the following distances apart : 165 mm., 40 mm., 

 85 mm., 70 mm., 80 mm., 40 mm., 150 mm., then back to 20 and 21 cm. 



mm. 



Length of hindfeet 60 



Width of hindfeet 20 to 25 



Length of forefeet 45" 



