DESCRIPTION AND DISTRIBUTION OF FOOTPRINTS 453 



A comparison of the tracks with existing newts and salamanders and 

 with the known amphibia of the Carboniferous and Permian serves to 

 establish an identification with the Stegocephs such as the Amphibamus 

 described by Cope * from the Carboniferous of Ohio. A form having the 

 size and shape of Melanerpeton of the Permian of Germany described by 

 Fritsch f might have made the tracks and the tail-groove. A salaman- 

 droid feature Avill be noted in the inward toeing of the fore foot and out- 

 ward pointing of the hind foot. Following the practice of Fritsch and 

 Marsh, the name Batrachichnus is here given to these tracks, with the 

 specific plainvillensis in allusion to the locality of their discovery. 



The two large footprints seen on the same slab (plate 40, figure 1) are 

 clearly distinct from the small tracks and show more of the characters 

 of Cheirotherium, in this respect resembling tracks found in the Nova 

 Scotia Carboniferous. These and other obscure prints of even larger 

 size in the Plainville district are too imperfectly known at present to 

 deserve further mention here. 



DISTRIBUTION OF FOOTPRINTS IN EASTERN CARBONIFEROUS AREAS 



The finding of these newt-like tracks in the Narragansett basin now 

 completes the tracing of these amphibians of the Carboniferous through- 

 out the remaining areas of the Carboniferous mud-flats of northeastern 

 America, except for some local basins in which it is probable that the 

 rocks are too much altered for the identification of delicate imprints. 



The moist and cool habitats of the existing land forms of the present 

 period is entirely consonant with the theory of Croll that the later Car- 

 boniferous was a time characterized by a lowering of the temperature 

 over the lands of widely separated areas. This local refrigeration of cli- 

 mate was probably in part due to elevation of the land. The extreme 

 to which Carboniferous climate was carried by this or other causes is 

 evident from the glacial records of India and Australasia. The faculty 

 of withstanding a period of freezing, as shown by Dufoy, explains in 

 part the persistence of the amphibian type from the Carboniferous to 

 the present day. 



CONDITIONS UNDER WHICH FOOTPRINTS WERE MADE 



M. Stanislas Meunier has claimed, on the basis of certain experiments 

 in the artificial production of buried footprints, that the fossil impressions 

 have been made upon a water-covered surface, and that where overlain 

 by sands this cover has been deposited by the action of winds blowing 



* E. D. Cope : Proc. Acad. Nat. Sci. Phila., 1865. 

 f Antoji Fritsch ; per Fauna der Gaskohle, 



