ESSEX COUNTY. 271 



luscous animals ; for while the latter appear to survive long periods, and occur in two or more 

 distinct rocks, fucoids arc strictly confined, if not to a few strata, at most to a single distinct 

 rock. 



The position of the principal mass, designated Fucoidal layers, is between the Potsdam 

 sandstone and the Calciferous sandrock ; but to which of these rocks it is to be considered as 

 subordinate, I am unable to determine, neither is it of much consequence. This mass, how- 

 ever, i.s to be distinguished from layers of fucoids which occur quite uniformly in the calci- 

 ferous sandrock ; for after the latter rock is distinctly formed, I have often found a repetition 

 of the fucoids, but much more limited than the mass below. From this fact, the fucoids 

 appear connected with, or subordinate t > the calciferous sandrock. 



I proceed now to speak of this mass as it occurs in Essex county. The first appearance of 

 it in the south, and within the limits of the county, is at Crown-Point, about two miles north of 

 the village, on the road leading to the old fortification. It has a northerly dip, and is exhibited 

 in two or three distinct uplifts. It bears the water-lime, or the drab-colored layers which are often 

 employed for hydraulic cement. The whole mass is thin, being only about twenty feet thick. 



Proceeding north to Cedar point, the calciferous appears resting upon the fucoidal layers, 

 or it is the upper portion of the sedimentary mass at this place. It is quite limited in extent, 

 and requires no farther notice, except to remark that it is destitute of fossils, and is confined 

 to the lowest layers of the mass. 



Proceeding still farther north, we find the calciferous two miles and a half south of the 

 village of Westport upon the lake, and it is now in company with the chazy limestone. Near 

 the village, and again half a mile south, the rock appears in beds suitable for flagging, and 

 the various purposes of building. It is of the ordinary variety ; and near the village, geodes of 

 crystals are common in the mass. A mile north, the primary, consisting of gneiss and horn- 

 blende, forms the north shore of the bay ; and for seven or eight miles, these rocks occupy 

 the whole shore in high perpendicular bluffs, as far as Split-rock. This forms the termina- 

 tion of one of the ranges of mountains which has already been described. The shore from 

 Westport to Essex forms the boldest scenery of the lake ; and viewed from near Basin harbor 

 on the Vermont line, it forms a scene truly magnificent. 



The last appearance of the calciferous in Essex county, is about three or four miles west 

 of Essex village, near Ross's bridge. Probably it continues down to Willsborough falls, 

 where it forms the principal rock at the mills, and is laid bare by the Bouquet, which flows 

 over it. It is geodiferous at this place, and presents the usual characters of this mass. It 

 either passes, at the lower part of the falls, into the potsdam sandstone, or it is the same rock 

 more highly charged with silex. Between the falls and Essex village, it is traversed by a 

 trap dyke, which has altered the adjacent parts several inches upon each side ; the alteration 

 consisting in greater compactness and hardness, together with the ability to break with a con- 

 choidal fracture. The action of the dyke is very distinct as well as instructive, showing 

 clearly the state and condition of the mass when it was injected. 



In Essex, this rock is of less extent than the sandstone beneath. Comparing it as it 

 appears at Chazy in Clinton county, and at Whitehall in Washington county, it is compara- 



