Geofogy and Mineralogy. 385 



sandstone in the Coal Measures, to what is called the Upper 

 Catskill or Pocono group (Rogers's Vespertine. \o. 10) inclusive, 

 at least 3,777 feet; Devonian strata. 7.075 feet ; ( )riskany sand- 

 >t J" u ' (which is referred by some to the Devonian and others r<> the 

 Upper Silurian) 58 feet ; Upper Silurian 4,214 feet ; Hudson I fiver 

 and Utica si .: least 2,370 feet— makin" in all 



18,394 feet. 



In the section, the Pocono sandstone has a thickness of 2,133 

 feet, and is overlaid bv the Mauch Chunk Red Shale (Rogers's 

 I moral), 1,100 feet; the Pottsvil] -i.„,e grit, 



Kogers's Serai), 280 feet; and the Alleghany River (or Lower 

 Productive) Coal Measures, 204 feet. The Devonian eoninieiiees 

 with the Catskill Red sandstone (lingers'* Ponent), 2,6m) feet 

 thiek. and is underlaid by 90 feet of "transition strata" between 

 it and the next below; 1,860 feet of Chemung shales (Tergent) ; 

 1,450 feet Portage flags (Vergent); 325 feet Genesee slate (Upper 

 Cadvnt); i;.:.-, feel Hamilton shales (Cadent) ; 875 feet Mareellus 

 ! 'i;i'-k -hale (Lower Cadent); GO feet Upper Helderberg lime- 

 >tone(Pust-m,-ridian): .-^ feet (>:•:> Mian). The 



Upper Silurian includes 742 of Lower Helderberg beds (the upper 

 162 feet limestone); 440 feet of Onondaga marlytes; 1,960 feet 

 of Clinton shales and ore-rocks (the ore-rocks 53 feet thiek and 

 deluding two beds of ore 12 inches apart, the upper of 10 inches 

 I .ickness and the lower of 14 inches); 1,330 feet of Me- 

 Istone; 568 of Oneida sandstone (Levant). The Lower 

 hides Hudson River shale -no feet : Utica shale 1,<>70 

 feet ; Trenton limestone 500 feet. Below lie the Calciferous and 

 Potsdam, of unknown thickness. 



3. Notes xipon the Lower Helderberg rocks of Port jervis, 

 y. Y.f by Dr. S. T. Baerett.— The subdivisions and fossil eon- 

 tents of the Lower Helderberg and underlying nek- near this vil- 

 lage are sufficiently peculiar to warrant their de-cription. They 

 are situated in the midst of what has very appropriately been 

 called the Appalachian System; a system of long monoclinal 

 ridges fronting the Atlantic and sloping backward with varying 



dips toward the northwest. These m clinal ridges trending 



northeast and southwest are crossed more or less obliquely by a 

 secondarv and compensatory system of flexures trending nearly 

 north and south. The Lower and Upper Helderberg strata 

 together constitute, when elevated above the drift, a low mono- 

 clinal ridge extending paralh 1 with th. Shawangunk (pronounced 

 ^honguin) Moun dn t i distant \ n < mg from less than a mile 

 to three or four miles northwest of the < " ' 



:-line of that 

 transverse or secondary system of 

 Ridge 1 ' 



of anticlinal 

 l folds, which add very much to the jucturc<«[ueness 

 oi the long monoclinal sallev in which I'ort Jervis is situated. 

 The roads across this ridg< ire i ide nt ssarih n tl* synclinals. 

 * Abridged by the author from a paper upon the same subject m voL n, Ann. 



