120 [Nov., 1846. 



ence to his recent donation to the Academy, of a fine speci- 

 men of fossil tracks in the red sandstone of the Connecticut 

 Valley. 



"It may not be improper for me to add, that we were shown on 

 a large block of stone, by a gentleman connected with the quar- 

 ries, tracks resembling those of some of our land animals, per- 

 haps those of a mink in size. They were very distinct, though 

 rather lightly impressed, there being, I believe, two rows across 

 the stone. And that early last spring I found among some frag- 

 ments, thrown out in consequence of sinking a well deeper, in 

 Rockyhill, Ct., a specimen of fossil shell, or something having a 

 close resemblance to one. One side of it is very perfect, the 

 other is embedded in the stone, and is probably a small bi-valve, 

 nearly an inch in length, and near three quarters of an inch in 

 breadth. I sent it to Professor Silliman, with permission to 

 deposit it in the cabinet of Yale College. If a shell, it appears 

 to be the first we have any account of as having been found in the 

 sandstone of the Connecticut Valley. 



The suggestion that the fossil tracks may probably be those of 

 some Sauroid reptile, is doubtless worthy of attention. But from 

 the few observations I made during my four years' residence at the 

 University of that place, I am inclined to the opinion that they can 

 never be attributed to any other than biped animals of some type 

 or other. Where opportunity is afforded for the inspection of a large 

 number of successive tracks, they are found to be at regular 

 intervals, along a line in the direction of the motion of the centre 

 of gravity of the animals; and the line drawn through the heel 

 and centre toe makes but a small deflexion from the line of motion 

 of the animal. In all the tracks which I have carfully noticed, each 

 alternate track exactly resembles that which precedes it, and in 

 some cases where there is a slight peculiarity in one of the feet, 

 this fact is very apparent. The heel of the track does not exhibit 

 any sign of the impression of a portion of the leg adjoining the 

 foot, not even where the animal has passed up or down a small 

 declivity, as was the case with some tracks on that portion of the 

 specimen in your museum, destroyed by the workmen in our 

 absence. If uric acid is found only in the excrements of birds, 



