272 New York State Museum 



The Bold Mountain limestone (Ruedemann '14) named 

 from its occurrence in the fine quarries at the foot of 

 Bald mountain in Washington county contains a Beek- 

 man town fauna and it is suggested (Ruedemann '14, '30) 

 because of the southern Appalachian and Missouri fossils 

 found (Eccyliopterus planidorsalis, E. planibasalis, Ul- 

 rich MSS) that this limestone continues through the east- 

 ern slate belt aftd may form a part of the Wappinger ter- 

 rane in southeastern New York. This formation is of 

 Upper Canadian age and has a thickness up to 100 feet. 



The Deepkill shales (Ruedemann '02) are for the most 

 part equivalent in age to the Beekmantown limestones 

 but the uppermost graptolite zone carries a Chazy fauna 

 (Ruedemann). They were deposited in the Levis trough 

 farther east. These shales, formerly included in the 

 "Hudson River" group, as were the Schaghticoke shales 

 occur in the Hudson valley in the vicinity of Albany and 

 were named from the typical exposure in Grant Hollow, 

 Rensselaer county, along the Deepkill, a tributary of the 

 Hudson river from the east. The graptolite shales of the 

 Canadian and Ordovician in New York have been divided 

 into 20 graptolite zones, and three of these into well- 

 characterized subzones. The Deepkill shales carry five 

 of these zones (3 to 7) with seven subzones. From oldest 

 to youngest they are zones of Clonograptus flc.vilis, Phyl- 

 lograptus typus, Didymograptus (D. uitidus, D. exten- 

 sus), Didymograptus bifidus (with Gouiograptus geome- 

 tneus, D. similis) , Diplograptus dentatus (with Clima- 

 cograptus pungens, Phyllograptus angustifolius, Trigono- 

 graptus ensiformis). The Deepkill shales show an alter- 

 nation of limestones with shaly intercalations, sandy 

 shales and grits, thin-bedded shales, grits and limestones, 

 and limestones with greenish silicious shales and black 



