1*1*1* Ni:W V(»KK S'lA'lK .MlSKr.M 



of tlic wliorl: r» (' 1 I (' r () i» li (> n ]► a in Ins [fig. 170], cliarac- 

 terized by a iM-oadly-llariiiii-. nearly circular ajicriin-c and a faint 

 median dcllcciion of ihc lines of lii-ovkih. 



Tlie Irilobiles arc represented l)y 1 1 o ni a 1 o n ot u s d e k a y i 

 [fig. 177], a lai-giMdongate, lingnifonn species, willi faintly marked 

 pygidium, reetangnlai* glabella, sublriangnlai* oej)lialon, and 

 thorax scai-cely trilobate; IMi a c o ]) s ran a [fig. 178], charac- 

 terized by the broad snb])entagonal, strongly piistiilose glabella, 

 I)roniinent evc^, and nearly semicircnlar i)vgidium. 



The problematical marking, S p i r o p h y t o n v e 1 u m [fig. 

 17!)]. which dilTers from the species in the Esopus chiefly by its 

 smaller size, is also common in the sandy layers of the Hamilton. 



Sherburne formation 



The Hamilton sandstones grade n]>ward into a series of blnish 

 sandstones and greenish shales which constitute the Sherburne 

 formation of Vanuxein. West of Schoharie county, fix)m the 

 Chenango valley to the meridian of Cayuga lake, where this for- 

 mation passes horizontally into the yai)les shales of the Portage, 

 it is se])arated from the Hamilton beds by the Tully limestone 

 and the Genesee shales. In eastern New York these formations 

 are absent as lithic units, and the Sherburne directly succeeds 

 the Hamilton. Its thickness is 250 feet or over, and its fossils 

 when not merely plant remains, constitute together with those 

 of the succeeding Ithaca beds a modified Hamilton fauna, which 

 gradually disappears westward. In Greene and Ulster counties, 

 this formation is unfossiliferous with the exception of scattered 

 I)lanl remains and probably includes the horizon of the "North 

 river bluestone." 



The most accessible locality for the examination of this rock is 

 in the nppei- slopes of Moheganter hill as described in the sections 

 in chapter ."). 



Jn the Schoharie rivei- valley region the line of separation 

 between Ihe JIaniilton and Sherburne formations is not as clearly 

 shown f<u- pail of the distance as it generally is farther west. 

 This is due largxdy to the lusivv mantle of drift coverinir the 



