AN AMERICAN GEOLOGICAL RAILWAY GUIDE. (N.Y.) 



the want of a more definite term. They are probably composed of several formations which have 

 not been minutely studied, and are so metamorphosed, contorted, broken and wrinkled in almost 

 every conceivable manner, and so disturbed, inverted and involved with each other, that at present 

 their precise geology cannot be stated. See note 117 on this subject, by Prof. T. S. Hunt. 



1 17. GEOLOGY OP EASTERN NEW YORK. To the east of the Hudson River in New York we find 

 besides the Laurentian rocks of the Highlands, and small portions of Huronian, a great development 

 of the gneiss and mica-schists of the Montalban and of two other and very unlike series. The first 

 of these is the Lower Taconic, consisting of the Stockbridge limestone with quartzite and peculiar 

 slates. This series, together with the Primary crystalline schists, stretches up northward,j)assing 

 along the southeast side of the Highlands, and occupying portions of Eastern New York and Western 

 New England. On the northwest side of the Highlands, extending northward along the valley of 

 the Hudson, and as far as Lake Champlain, is found another series, variously designated as the 



ing Sillery and Levis). They are generally disturbed and often inverted, and include small outliers 

 and involved portions of Upper Cambrian and occasionally of Silurian strata. This Hudson River 

 and Upper Taconic group is distinct from and superior to the Lower Taconic. It is impossible in 

 the present state of our knowledge of their distribution to define the limits of these various groups 

 of strata to the east of the Hudson, or to say at what stations the Upper Taconic, the Lower Taconic 

 or the Primary rocks are met with. T. S. HUNT. 



118. GEOLOGY OF THE HARLEM RAILROAD. The Laurentian mountains forming the Highlands 

 on the Hudson River, from Peekskill nearly to Fishkill, (see note 6), extend as mountains only about 

 sixteen miles east of that river. The Harlem Railroad runs through valleys, and the Highlands are 

 not observable as a prominent ridge. Bat the series of formations is the same as on the river, con- 

 sisting first of the Laurentian foundation rocks; then, south of these, the later crystalline series to 

 New York City. North of the Laurentian, is the Great Valley, a thousand miles long, made up of 

 the groups variously called Taconic, Quebec, Cambrian or Lower Silurian. This valley, geograph- 

 ically at least, runs across the River Hudson at Newburg and Fishkill, (see note 7), and then runs 

 through the Taconic or Quebec belt to the City of Quebec in Canada. This district has been for a 

 long time the great battle-field of geologists. Its geology can perhaps safely be inferred to be the 

 same as in other portions of the same valley, where, from its fossils and the rocks above and below, 

 its place in the series can be fixed beyond question. 



119. The limestones and sandstones used for flagging and building in the various cities along the 

 line of the N. Y. C. & H. R. R. R., are as follows : At Albany, Schenectady, Utica and Rome, 4 a. 

 Trenton limestone, generally of the Birdseye portion, which produces the thickest stone; at Syracuse, 

 Auburn and Geneva, the 9. Upper Helderberg, genei ally the Onondaga or lower portion of it ; from 

 Rochester to Buffalo the 5 a. Medina sandstone is the favorite for these purposes. Some 5. Niagara 

 limestone are used at Rochester and 9. Upper Helderberg or Corniferous at Buffalo, especially for 

 lime burning. But the best flagstones are from the Hamilton and Chemung formations, and gener- 

 ally come from the shores of Cayuga Lake. Large quantities of flagstones are also brought from 

 the upper part of the Hamilton group in the higher parts of the Helderberg, and from the same 

 geological position along the west side of the River Hudson from below Catskill as far as. Kingston. 



