444 A. F. Foerste — Fossil localities in the early Paleozoics. 



and for a considerable distance southwards in western Yermont 

 and eastern New York. It is probably in part for this reason 

 that the geology of Rensselaer and Washington Counties is so 

 difficult to unravel and no longer presents the same simplicity 

 of lithologic structure found east of the Taconic range. 

 Lithologically this difference consists in the introduction of 

 argillaceous and sandy limestone, shale and sandstone elements 

 into that part of the early paleozoic scale which is represented 

 in New Jersey and southward by the Magnesian limestone, 

 and in the southern half of Yermont by the Stockbridge lime- 

 stone, in other words that part of the section between the 

 Hudson River (including for the present the Trenton lime- 

 stone in the great limestone series) and the top of the Olenellus 

 Cambrian sandstones. How far southward the sphere of 

 influence of the Adirondack sedimentation extended, is un- 

 known. To what extent, the Archaean of the Highland region 

 between Newburgh and Peekskill supplied sediments to the 

 early paleozoic series as here discussed is also still undeter- 

 mined. The remarkable agreement between the southern 

 Yermont and the New Jersey, eastern Pennsylvania, and more 

 southern sections and the great longitudinal extent of the area 

 having this structure would however lead to the conclusion 

 that these sections represented the main lithologic features of 

 eastern early paleozoic geology ; a basal Cambrian sandstone, 

 overlain by a great series of limestones embracing a con- 

 siderable vertical range of faunas, and a great mass of Hud- 

 son River slates and shales and sandstones, overlain finally 

 with more or less unconformable Oneida conglomerate, the 

 unconformability in many places being more theoretic than 

 evident structurally, while in others it is also strongly marked 

 structurally, and always paleontologically. Yariations from 

 this lithological type would seem to be due more to local 

 features, sometimes of vast influence as in the case of the 

 Adirondacks, at other times of more limited range. To study 

 out these more local influences as something distinct from the 

 general, to discover their source and their range is a part of 

 the geology of the immediate future. 



The various questions of correlation here discussed are of 

 course not new. They are here brought out again chiefly to 

 emphasize the strong agreement between the sections of the 

 early paleozoics in the southern half of Yermont between 

 the Taconic and Green Mountain ranges, and those of New 

 Jersey, eastern Pennsylvania and southwards, an agreement 

 the more remarkable since closely contiguous areas west of the 

 Taconic ranges, in western Yermont, and Massachusetts, and 

 in eastern New York do not show the same simplicity of litho- 

 logic structure. 



