﻿VIII. 



Illustrations of Fossil Footprints of the Valley of the Connecticut. 

 By JAMES DEANE, M. D. 



(Communicated to the Academy, August 8lh, 1849.) 



The beautiful footprints upon the sandstone strata of Connecticut River were 

 discovered in the year 1835. They indicate the existence of vertebrated, air-breathing, 

 and warm-blooded animals at a remote period of the earth's geological antiquity ; com- 

 prising at least two classes of the animal kingdom, Aces and Reptilia. 



The number and perfection of these remarkable relics, the huge size of many of the 

 creatures by whom they were impressed, and the consideration of the remote epoch 

 in which they lived, invest the subject with intense interest. To myself, their study has 

 for many years been in the highest degree attractive, and my labors in the field have 

 invariably been compensated by successful discovery. As a result of the investigation, 

 I respectfully offer this brief memoir. I have no intention of entering fully into the 

 subject ; my plan is merely to present some obvious practical views, grounded upon 

 facts, leaving purely speculative conclusions out of the question. I do not even attempt 

 a classification of the footprints. The creatures that made them existed in immense 

 numbers, and unquestionably belonged to numerous families, genera, and species ; yet to 

 distinguish them all by strict rules of classification is absolutely impracticable. The 

 forms of the footprints are extremely diversified, even in unblemished impressions, and 

 glide into each other by insensible gradations. But insurmountable obstacles are pre- 

 sented in the various conditions of the stratum at the time the animal walked over it, 

 and in the changes which the tracks must have, in many cases, subsequently undergone. 

 If the surface whereon the creature trod was consolidated by desiccation, a superficial 

 flattened impress resulted; if yet too soft, the impression must have closed in; and be- 

 tween these extreme conditions there are infinite modifications of form. I apprehend 

 that another difficulty in the way of classification arises from the fact, that the footprints 



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