CLINTON GftOUP. 



2§ 



evidence of the nature of these markings. The stratum on which it is made is a level sandy 

 surface, vs^ith a slight coating and intermixture of shaly matter. 

 Position and locality. Quarries near New-Hartford. 



PLATE XII. Figs. 1, 2, 3, 4. 



Fig. 2. A specimen similar to fig. 4 upon the preceding plate^ but the trail is stronger and 

 deeper, and the ridges of sand thrown up on the sides much higher than in any other one. The 

 windings of the trail are much more extensive than either of the others, and correspond in this 

 respect to the size of the animal. Both in this and the preceding specimen, there is a slight 

 bending of the older or first made track visible where it is crossed by the newer track, showing 

 that the progress of the animal across a previous track produced a motion in the wet sand be- 

 yond the extension of its body. These appearances are not so clearly represented in the figures 

 as they appear in the stone. 



Position and locality. Blackstone's quarries, New-Hartford. 



Fig. 3 is a small portion from a specimen covered with trails of this character, where the 

 margin of the track is marked by coarser particles of sand which have evidently been pushed 

 out laterally during the progress of the animal. This is, to some extent, visible in the other large 

 tracks, and depends in part on the consistence of the material. Many of these tracks are partially 

 filled up by the moist sand and mud which flowed back into the trail after the passage of the 

 animal. This will be readily understood by any one who has witnessed the action going on in a 

 wet sea beach or elsewhere, where wet sand is disturbed and afterwards left at rest. 



In the same specimen, at the right of the principal track, are some remains of very minute 

 tracks which are found meandering among the coarser ones. 



Position and locality. Quarries near New-Hartford, Oneida county. 



The tracks thus far noticed appear to belong to a single class of animals, and of species 

 varying in size. Some of them may, indeed, be due to animals of the same species in different 

 stages of growth ; and from the impossibility of finding means of proper distinction, I have not 

 attempted to distinguish species, since nothing could be gained at this time by such an attempt. 

 The preservation of such minute markings upon surfaces which must afterwards have been 

 subjected to the influx of water (or which were at the time beneath water), and the subsequent 

 deposition of other materials upon them, is truly wonderful, and might reasonably be doubted, 

 but that we have the most unquestionable proof of their origin, connected at the same time with 

 other evidences of the existence of beaches at the same period. 



Fig. 1 ( pi. 12) appears to be a cast of one of these trails, upon the lower side of a thin layer 

 of sandstone. This cast presents a narrow depressed line along the centre, and a broader eleva- 

 tion at each side. This specimen is interesting, as showing, that in some instances, the nature 

 of the subsequent deposition has been such as to preserve the form of these tracks. 



Position and locality. Ruddock's quarry near the village of Clinton, Oneida county. 



