liH Ni:W YORK STATI-: ML'SEUM 



typo. As already noted, similar ones are found on the surface 

 of the upper quartzite of the Oriskany. 



'IMie lliickness of the Esojnis on AVest hill is scarcely over 90 

 feet,i while on East hill the measurements j»ive only about 80 feet. 

 At Countryiii;ni liill near New Salem tlie thickness of this forma- 

 tion is 121 feet; at Clarksville 121 feet; at Becraft mountain and 

 at Rondout about 300 feet including the Schoharie, and at Port 

 Jervis about 700 feet. Except the structure described as 

 8 }) i r p h y t o u ( T a o n u r u s) c a u d a - g a 1 1 i no fossils 

 have been found in the Esopus shales of this region. 



Sequence of events during Lower Devonic time 

 With the comi^letion of the deposition of the Manlius limestone, 

 i. e. at the end of Siluric time, there appears to have Ixvn a g'en- 

 eral elevation of the North American continent into dry land,- 

 with the exception of a long narrow sea, which extended along the 

 western border of the old Appalachian continent (Appalachia) 

 and between it and the newly elevated continent on the west. In 

 this sea which has been named the Cumberland basin,^ the Hel- 

 derbergian strata were deposited, resting directly on the Manlius 

 formation and continuous with it in the central portion of the 

 basin. Western New York and the whole ^Iississip})i region, be- 

 ing above sea level at that time, were actively eroded, till at the 

 l)eginning of Oriskany time, only 7 feet (the Cobleskill member) 

 of the Manlius remained in western New York; from 300-100 feet 

 in ^lichigan; and not over 30 feet in southeastern Wisconsin 

 where it rests directly on the Guelph.^ Westward from this point 

 the Manlius, if once })resent, w^as entirely removed by erosion, and 

 farther west the whole Siluric is wanting. The fact that late 

 Devonic rests on late Lower Siluric in sonie localities suggests 



'Those ineasiirenuMits arc made by careful levoliuc: from the top of the 

 Oriskany to the l)nse of the Schoharie or the Onondajjca [sec sections in 

 ch. 5]. The thicknesses lieretofore pnblislied for tliis fonuation in tlie 

 Selioliarie rej^ion are mostly too larj?e. 



2 The Cayugan emergence of Ulrich and Schuchert. 



^Ulrieh & Schiiciiert. Paleozoic Seas and Barriers in Eastern North 

 America. N. Y. State Taleontol. An. Uej)t for 1901. i).G47. 



* These dolomites (Monroe) may in part represent the Saliua. 



