320 Prof. Hitchcock on Ichnolithologij , or Fossil Footmarks. 



ness yet made. That contains the originals from which the 

 thirty four species have been described and figured. It consists 

 of specimens of all sizes, from two or three inches square to a 

 slab twenty three feet long, containing seven most distinct tracks 

 of the huge O. giganteus in succession. There are also the 

 rain-drops and the coprolites. At present the number of speci- 

 mens is one hundred and fifty. 



As it is now becoming very difficult to obtain good specimens, 

 such as are wanted in large collections, I may be allowed to say, 

 that I know of a few places where probably with considerable 

 labor very good specimens may be obtained, and I will attempt 

 it if desired. 



Such is the history of footmarks. When Dr. Duncan in 1828 

 gave a brief account of the tortoise tracks of Scotland, he was 

 by no means aware what a curious field he was opening to geol- 

 ogists. And the numerous cases that have been brought to light 

 within the last sixteen years, now that the attention of geologists 

 has been directed to the subject, illustrates a quaint remark of 

 Dr. Macculloch, that we need to be taught to see. And now 

 that geologists have their eyes open to this subject, we may an- 

 ticipate many more curious facts and results. 



And really this new field promises much fruit to geologists. 

 It has already learnt them to be cautious in asserting the non- 

 existence of land animals from the absence of their remains in a 

 formation. In the valley of the Connecticut, for instance, more 

 than thirty species of such animals, some of them of giant size 

 have left no other certain evidence of their existence save their 

 footprints and a few coprolites. And we can hardly believe that 

 birds were the only vertebral animal that dwelt in that valley 

 during the red sandstone period. It would be illogical, indeed, 

 to infer from hence that we know almost nothing respecting the 

 fauna of the ancient world from exhumed relics. But it does 

 teach us caution in our inferences as to the proportions of differ- 

 ent classes. 



This subject, too, has more than one valuable moral. It shows 

 us that the most trivial movement of ours may make an imp"" eS * 

 sion on the globe that shall be brought out ten thousand ages 

 hence with unimpaired freshness— that shall in fact be immortal. 



■ 



5 



No geologist will think it at all extravagant to speak of the pe- 



riod when these tracks were impressed on the new red sandstone 



