106 ROYAL SOdiETY OF CANADA 



of the fore foot is sometimes found proportionately longer than that 

 of the hind. Asperipes avipes, A. flexilis, Baropezia Sydnensis. 



The " caudifer " species of the Carboniferous tracks have their 

 counterpart in the alligator track, reproduced by Dr. Dean, where the 

 imprint of the keel of the belly and its scutes have left a distinct im- 

 pression between the footmarks of the right and left sid.es of the body. 

 Hylopus caudifer, Dn,, H. minor, Dn., Batrachichnus plainvillensis. 

 Wood., S. primaevus. Lea (sp.), Nanopus oaudatus, Notolacerta Mis- 

 souriensis Btt. 



While the foot prints of the frog and the alligator reproduce many 

 characters which are to be found in the Carboniferous footmarks, there 

 are peculiarities of form in the latter that are not to be found in the 

 former, and we are led to suppose that neither the modern Amphibians, 

 nor the Eeptiles, nor both together will present to us all the varied 

 modificafions which the ancient footsteps of the Carboniferous age 

 record; and we are open to accept the conclusion of Sir Wm. Dawson 

 that the Labyrinthodonts and the Microsaurians are responsible for 

 many of these characteristic batrachian tracks. 



The habits of these animals thus known from their footprints left 

 in the sand and the mud is a matter of conjecture, though the number 

 of those preserved at the Joggins suggest the existence there for some 

 time of such estuarine conditions as conduced to the preservation of 

 that wonderful series of tracks of the Triassic period which were found 

 by Prof. Hitchcock, Dr. Deane and others at the famous locality of 

 Turner's Falls, on the Connecticut river. 



In a number of instances we have observed that the Carboniferous 

 tracks run up or down the mudflat, as though the animals that made 

 them were in the habit of visiting the shore at low tide, where not only 

 would they find a larger assemblage of animals of the sea of the lower 

 orders, but where would also be dead and dying organisms among wihich 

 these scavengers from the land found appetizing morsels. 



On the other hand, if any of these animals were marine as are some 

 of the Chelonia,ns, they may like the turtles have resorted to the beach 

 for the purpose of laying their eggs in the dry sand at the top of the 

 beach. A practise of this kind would have given rise to the numerous 

 tracks that go up and down the beaches of Carboniferous Time at the 

 Joggins. 



In looking for a relation in the length of the stride and the width 

 apart of the right and left footmarks, one is puzzled to note how foot- 

 marks which are sufficiently alike to be placed in the same genus, differ 

 from each other in this respect, as the following list will show. In this 



