78 Geology, ire. of the Connecticut. 



Fig. 3. is probably the same as Fig. 2. ; but perhaps not. 

 The outline is given because the fins were more distinct 

 than in the specimen from which Fig. 2. was copied. 



These are all of the natural size. Concerning their names, 

 feeling altogether incompetent, I do not even attempt to de- 

 cide. I have not had an apportunity to compare them close- 

 ly with the Westfield icthyolites, and do not know whether 

 they coincide. 



Another petrifaction occurs with these fishes, which re- 

 sembles the common silver eel, (Muraena angmlla,) or some 

 other species of the eel tribe. The width varies from half 

 an inch to a whole one, and the length from one to two feet. 

 The substance of the eel (if indeed it be one,) is not con- 

 verted into coal, but there is a substitution of the shale of a 

 finer grain, except the head, which is coal. No fins appear, 

 except, perhaps, in one instance, a pectoral one. Some- 

 times, along the centre of the impression, there is a small 

 relief, answering to the place of vertebrae. The course of 

 the impressions is usually serpentine. 



The geological situation of these icthyolites is interesting. 

 The shale containing them passes under Mount Toby, there 

 being a gradual ascent from this spot to the top of the 

 mountain, two miles distant : so that they lie beneath rocks 

 of the coal formation at the depth of nearly nine hundred 

 feet, most of the varieties described on the profile annex- 

 ed to the map here alternating with one another. The fol- 

 lowing sketch exhibits a section of the shaie of Mount Toby, 

 so far as the geest would admit of examination, on a line 

 passing from the locahty of the icthyolites to the highest 

 point of the mountain. I do not suppose it perfectly accu- 

 rate , but it is probably sufficiently so to answer the intend- 

 ed purpose, viz. to exhibit the situation of the ichthyolites. 

 The numbers in a parenthesis refer to those on the profile 

 that are synonymous. The dip of these strata rarely ex- 

 ceeds ten degrees, and is usually less. 



No. 1. (No. 59.) Very Coarse dark grey pudding-stone^ 

 for an account of it see the reference to the profile, on 

 plate No. 8. at the end. 



No. 2. Bituminous Shale. This contains icthyolites — 

 strata nearly horizontal — dip never exceeding five degrees. 

 Thickness of the stratum, about ten feet. 



No. 3. Same as No. 1 . except sometimes alternating with 



