REPORT OP THE STATE PALEONTOLOGIST 1902 1001 



lowed, from the point where it crosses the Portage town line. 

 In this distance the river descends 100 feet, and the southward 

 dip of the strata is 32.5 feet a mile. 



The Portage town line is 9 miles south of the mouth of the 

 gorge at Mount Morris, and the dip therefore adds 292 feet to 

 the thickness of the exposed strata and gives a total of 392 

 feet, of which all but 65 feet are included 

 in the " Portage group " as described and 

 limited by Prof. Hall. 



The Styliola or Genundewa limestone 

 of the Genesee shales, which is 82 feet 

 above the top of the Hamilton shales in 

 the ravine of Little Beards creek at Lei- 

 cester, 3 miles north of the mouth of the 

 gorge, is exposed in the banks near the 

 west end of the Western New York and 

 Pennsylvania Railroad bridge at Mount 

 Morris, and, with a few feet of black 

 slates below it, is the lowest rock ex- 

 posure on this section of the river. 



About 65 feet of typical upper Genesee 

 shales overlie the Styliola limestone and 

 are exposed at the east end of the cov- 

 ered highway bridge at the mouth of the 

 gorge, where the spheric concretions and 

 characteristic fossils of this horizon are 

 common. 



At the top of these bluish black shales 

 there are a few lighter colored layers, 

 some clayey, others slightly arenaceous, 

 distributed through about 3 feet of 

 darker shales. At this horizon a lighter 

 band, hardly noticeable here, but fully developed farther east, 

 has the sedimentary characteristics of the Portage shales and 

 flags and contains a few fossils from both the Genesee and the 

 Portage faunas. 



Overlying these passage beds there are 32 feet of densely 

 black and bituminous slaty shales iu which plant remains are 



ft 



light and dark 

 shales with 

 flags 



blue and 

 black shale 



light shale 



black shale 



Cashaqua 

 shale 



Fig. 2 Section in Buck run 

 ravine at Mt Morris, above 

 Cashaqua shale. Stations 4, 5 



