Two New Species of Fossil Footmarks. 



49 



made by the right and 

 left feet of the animal : 

 and hence I was forced, 

 contrary to my first im- 



Fig. 1. Reduced 18 diameters 



pressions 



i 



to regard the 



animal as a biped. In 

 attempting to trace its 

 analogies to living ani- 

 mals, however, I have 

 been less successful than 

 in respect to any other 

 animal of the thirty or 

 forty species that impres- 

 sed the forming new 

 red sandstone of New 

 England. Indeed, the 

 enquiry has recurred to 

 me more forcibly than 

 ever, whether some of 

 these animals may not 

 have combined in their 

 structure, characters now 

 found in several distinct 

 races ; as seems to have 

 been the case with some 

 of the Saurians. But 

 this suggestion can be 

 judged of better after de- 

 scribing the footmarks 

 under consideration. 



On the same slab with 

 the large tracks, are those 

 of two other species of 

 thick toed bipeds : one of 

 which is the Brontozo- 

 t«m Sillimanium, (Orni- 

 thoidichnites Sillimani 

 ot my Report,) and the 

 other a new 

 which I have 



species 

 denomi- 



nated B. parallelum, on 

 account of the slight di- 

 vergence of the lateral 

 toes. I shall first describe 

 the genus Brontozoum, 

 and then this new spe- 

 cies, in the manner in 

 which I propose in fu- 

 ture to describe all the 

 species known to me. 



Second Seriks, Vol. IV, No. 10.— July, 1847. 



7 



