THE FOSSIL FOOTMARKS OF THE UNITED STATES. 135 



er, and afterwards to copy them on thin paper placed over the 

 mica. When reduced subsequently, the proportions were accu- 

 rately preserved, 



I ought here, however, to consider an opinion, which I have 

 met occasionally, and which goes against the whole system of giv- 

 ing scientific names to fossil tracks, or to the animals that made 

 them. It is considered a useless show of learning, because it 

 is supposed that the data afforded by tracks alone are not definite 

 and full enough to discriminate species, which can be done only by 

 the discovery of their skeletons. 



I take a different view of this subject, and maintain, that, by 

 the principles of fossil zoology, we are fully justified in classifying 

 and naming animals from the evidence of their tracks alon« ; and in 

 support of this opinion, I offer the following reasons. 



In the first place, no naturalist who has seen a good suite of these 

 fossil footmarks will doubt that they prove the existence of certain 

 animals during the deposition of the new red sandstone of the 

 Connecticut valley. Many are skeptical on the subject till they 

 have actually seen good specimens ; but a glance of the eye usually 

 carries the conviction to the mind, that the tracks were made by 

 animals, almost as certainly as if their skeletons were standing 

 before the observer. 



In the second place, these extinct animals have never been 

 described. Very few vertebral animals have been found in the 

 new red sandstone of any country, and none in that rock in our 

 country, save fishes. Those which have left only their tracks, there- 

 fore, deserve names as much as any other animals, living or fossil, if 

 we can find out what are their characters. 



In the third place, every one who examines these tracks admits 

 at once that they were made by several distinct species of animals. 



