Gushing — Geology of Clinton County. 



55 1 



Calciferous sandroch Rocks of Calciferous age apparently form the 

 surface over most of the eastern third of the township, although no certainty 

 can be reached upon this point, due to the scarcity of exposures. The out- 

 crops are small and isolated, and generally give no clew to their horizon in 

 the Calciferous, being for the most part of the iron-grey dolomite which consti- 

 tutes such a large part of the formation. Just north of Lapham's, are meagre 

 outcrops of very sandy dolomites, which weather to deep ferruginous, sandy, 

 brown crusts, and seem to belong to Division D, of Brainard and Seely. 



Along the lake shore, both north and south of Valcour, rocks of this age 

 outcrop for a distance of a mile or more. The major part of the rock is a 

 hard grey dolomite, full of seams and balls of calcite, and in some layers quite 

 fossiliferous. Interstratified with them are thin bands of limestone, more 

 abundant toward the top. Here limestone is also found in irregular lenses, 

 which are full of fragmentary fossils, looking as if they had been worn on a 

 beach. An OpMleta-fflze form also occurs, and is the only species found 

 entire. The rocks lie in a series of low east and west folds, with a slight 

 fall of the w hole toward the north. They are well toward the top of the 

 Calciferous, and are followed a short distance to the north, apparently 

 conformably, by the lower Chazy. The whole mass is penetrated by irregular 

 slaty seams. 



'' Chazy limestone. From Valcour northward along the lake shore, rocks 

 of Chazy age outcrop in a belt about half a mile wide, abruptly terminating 

 on the west along a fault line, the Bluff Point fault. The exposures are 

 rather infrequent, and the district needs detailed study, but everything seen 

 seems referable to the lower part of Division A, of the Chazy. On Mr. Day's 

 land two quarries have been opened in the rock, one near his house and one 

 by the lake. In the upper quarry especially, the rock is quite fossiliferous, 

 and good collections can be made. A large Nautilus is conspicuous among 

 the fossils. Mr. Day has an excellent Lituites obtained from the quarry. 

 Trilobite fragments abound, mainly of Illcenus and Harpes, and several 

 species of brachiopods are present, Orthis costal/is being the most common 

 form. The locality is one of considerable palaeontologic interest. 



Series V. Eight dikes have been found in Peru, of which six are 

 diabases, and call for no special mention. The other two cut the Chazy lime- 

 stone, near the lake shore, and are of interest on account of the rarity of dikes 

 in the county outside of the pre-Cambrian rocks. 



No. 2, in the field just south of the Day quarry, is a typical camptonite, 

 the only one so far found in the county. It may be traced clear to the lake 



