Report of the State Geologist. 



23 



In North Hudson, so far as explored, only the gabbros have been noted. 



In Schroon, the gneisses and crystalline limestones cover almost the entire 

 township except the northern portion where there are gabbros, and a small 

 area at Schroon Lake post office, correctly regarded as Calciferous sandrock. 

 The last is the remotest outlier yet observed of palaeozoic sediments in the 

 mountains. Several dikes are noted ; one at Pharaoh pond, others west of 

 Schroon Lake post office. Iron ore occurs in the Schofield bed at the extreme 

 east of the town. 



Minerva is chiefly covered with gneisses and crystalline limestone ; on 

 the northeast, gabbros and related rocks occur, and the same are present along 

 the eastern border. No palaeozoic rocks or dikes were met with. There is 

 little iron ore in the town, and garnet is worked at one locality for an abrasive. 



Newcomb has been but partially studied. The gneisses and crystalline 

 limestones are widespread ; the folding of the latter has been an important 

 factor in producing the lake basins in the central part of the town and in de- 

 termining the water courses. The anorthosites and gabbros make up the 

 eastern third of the township. No palaeozoic rocks or irruptive dikes have 

 been observed in the town. In the vicinity of lakes Sandford and Henderson 

 are extensive iron mines. These mines were opened at the village of Mc- 

 Intyre and bloomeries established about 1835, by the late Hon. Archibald 

 Mdntyre. A very complete history of their workings, with a description of 

 the ores, analyses, and a map of the mines, are given. The amount of ore in 

 sight is enormous, and though highly titaniferous, it is thought that it may be 

 profitably worked with the revival of the iron demand and an improvement 

 in shipping facilities. 



The geologic notes made upon the separate townships are often in con- 

 siderable detail, involving careful analyses of rock structure and derivation. 



Thickness of the Lower Silurian Formations along West Canada Creek and 



the Mohawk River. 



By Charles S. Prosser and Edgar S. Cumtngs. 



The writers here consider in extemo the rock sections exposed in the 

 gorge of the West Canada creek at Trenton Falls, at New port and at Little 

 Falls. 



These sections have all been previously studied by other observers, some 

 of them frequently, and not always with concordant results. In this paper, 



