ESSEX COUNTY. 281 



Tl>e grit-rock of Snake mountain is equivalent to the grey sandstone above the Loraine 

 shales ; the latter of whicli, the reader is to bear in mind, is simply a synonime of the Hud- 

 son river shales, both terms being occasionally used to designate the same rock : they differ, 

 as has been already pointed out, only in the physical changes which each has sustained. 

 At I^oraine, they are but slightly removed from a horizontal position ; while along the Hud- 

 son river, they have been fractured and elevated in a high angle, or a steep dip to the east 

 has been given them. 



The fracture here spoken of, is one of the most interesting and remarkable of all the 

 geolou-ical phenomena which have been disclosed during the New- York survey. At Snake 

 mountain, it is particularly worthy of notice. As has been stated, from the lake to its base, 

 it is seven miles ; the whole distance is level, and the tertiary is the only formation which 

 appears, but we know it rests upon the shaly part of the trenlon limestone. The rock then 

 continues to the great fracture at the base of the mountain ; and we find, when we commence 

 the first ascent, that we have left the rock just named, and have passed from that to the calci- 

 ferous sandrock. Wc leave the trenton slate at the base of the mountain. After passing 

 over the calciferous sandrock, we soon find ourselves upon the chazy, then upon the trenton 

 limestone, utica slate, and Hudson river shales, each in its order, as we ascend the mountain, 

 till finally we reach the base of the cliff composed of a hard grit rock, the upper part of 

 which is a grey limestone. Sometimes this mass is calcareous throughout its whole extent, 

 effervescing strongly with acids ; and then again it is very deficient in lime, the whole mass 

 being mostly siliceous. I know of no rock, especially if we take in the grey even-bedded 

 sandstone just cited, so given to change ; it is sometimes a rubble, sometimes brecciated, and 

 again calcareous in various degrees. It is often green, reddish or brown, and frequently the 

 upper part is a pure white limestone. 



The fracture at the base of this mountain may be traced a great distance north, appearing, 

 however, more distinct where the uplifts are the greatest. The direction and bearing of this 

 fracture being once known, it is easily traced ; but in order to state the facts revealed, and to 

 enter upon details in relation to it, more investigation is required than I have been able to 

 give it. 



I shall now proceed and speak of the rocks at Charlotte, opposite the village and township 

 of Essex. At this place, their order and position is much the same as at Addison. The 

 shore upon the Charlotte side is formed of the trenton limestone : it continues halt a mile, 

 with an easterly dip ; when it thins out, and we pass to the chazy limestone, with a dip to 

 the west. The rocks are, however, much concealed, until we ascend the hill upon which 

 most of the village stands. Near the church, there is a fine outcrop of the grit-rock which 

 has been described. It is here in regular beds, and they are strictly a sandstone, the particles 

 of which are angular, but not coarse. At Charlotte, the rock is reddish brown, and the whole 

 mass is siliceous, the grey limestone being wanting. As a whole, it has quite a strong resem- 

 blance to the old red-sandstone. There is, however, one particular in which the sandstone 

 differs in all its phases from other siliceous rocks : the particles of quartz are hyaline, or have 

 a translucency which we do not discover in other sandstones ; and the mass, though red, is 



Geol. 2d Dist. 36 



