1847,] Geology of Lewis County. 321 



Chimney point derives its name from a fancied resemblance of 

 a vast triangular pyramid, formed by the junction of two gulfs, 

 to a chimney. This is on Roaring brook, about two miles west 

 of the village; is easy of access, and can be seen to advantage 

 without descending the bank. 



On the left of the ' Chimney' is a beautiful cascade, falling 

 from the bottom of a ravine, which has worn a channel about half 

 way down the cliff, and whose murmur is the only sound that 

 breaks upon the stillness of the magnificent scene. 



Both of these localities are interesting, from their number and 

 variety of fossil remains. 



The junction between the Trenton limestone and Utica slate, 

 is not seen in the county, being concealed along the water-courses 

 by the debris brought down from the gulfs. This slate is of a 

 black color, and where exposed to the weather, brown; fissile, 

 and divided by vertical joints in three directions, which do not 

 preserve a uniformity in their course. None of these joints are 

 uniformly parallel, except those which were N. 35° W., "at several 

 localities. The other systeujs of joints cut this obliquely at vari- 

 ous angles, and one of them is not usually present. 



The whole thickness of the Utica slate may perhaps be one 

 hundred feet, and at several places the dip was very gentle to- 

 wards the southwest. Occasionally thin veins of calcareous spar 

 occur in the joints, or occupying thin strata between its lamina?, 

 which, with the exception of a sulphuret of iron replacing an 

 orthoceratite, are the only mineral contents of this rock. 



Towards its upper part, the soft black shale, which properly 

 constitutes the Utica slate, alternate with thin strata of a hard 

 gritty rock, which, in mineral character as well as fossil contents, 

 indicates a transition between the Utica slate and Loraine shales. 

 Specimens of the Triarthus Beckii, which is a characteristic of 

 the Utica slate, have been observed associated with individuals of 

 the genera Pterina, Cyrtolites, Trinucleus, and Cypricardites, 

 equally peculiar to the Loraine shales. 



As a fact of some interest, as illustrating the range of organic 

 life in the earlier rocks, it might be mentioned, that a specimen 

 of the Pterinea carinata was found near the bottom of the Tren- 

 ton limestone, at Deer river falls, in a thin stiatum of shale. 

 The proper place of this fossil is in the Loraine shales. 

 In no part of this series have I observed a rock that can with 

 propriety be referred to that division of the Hudson river group, 

 called the Frankfort slate, as there is no considerable portion 

 destitute of organic remains, or possessing the characters of that 

 rock. 



At about that place, where the transition character of the rock 

 renders it doubtful to which formation to refer it, there occurs a 



