400 Nezv York State Museum 



for the Genesee black shale occur; also the pelecypods 

 Lunulicardiiim curtum, Panenka sp., and the crinoid 

 Melocrinus clarkei. The Standish flags and shales 

 (Clarke and Luther '04) are thin, uneven, bluish gray 

 flags and olive shales, with a thickness not exceeding 15 

 feet, and representing the transition in west central New 

 York "from the argillaceous shales of the West River 

 beds into the arenaceous sedimentation characterizing, 

 for the most part, the mass of the Portage strata." The 

 name is from Standish gully, near Italy, Yates county, 

 and the formation is a local one. The Middlesex shale 

 (Clarke '03; Luther) was named from the occurrence in 

 Middlesex valley, Yates county, and was at one time in- 

 cluded in the upper Genesee beds. It was later called 

 (Clarke '85) the "Lower black band" of the Portage. 

 These are densely bituminous deposits (20 to 40 feet, 

 more or less, in thickness), similar to the Genesee black 

 shale and with a meager fauna showing affinities with 

 that of the Cashaqua shale (Hall '40). These latter are 

 light, soft, rather calcareous shales (50 to 125 feet, more 

 or less) succeeding black shales and limited at the top by 

 similar bituminous shales. They extend from Lake Erie 

 to the Cayuga lake region where they become involved 

 with the Sherburne flags( Ithaca fauna). In these soft 

 shales the peculiar western Portage fauna (Naples) at- 

 tained its culmination. In the midst of the Cashaqua 

 shales in west central New York (Canandaigua lake 

 region to Seneca lake) is a limestone lentil, the Parrish 

 limestone (Clarke and Luther '04) characterized by a 

 singular composition of greenish and reddish calcareous 

 nodules and carrying an abundant goniatite fauna. In 

 the recurrent beds of black shale above the Cashaqua, the 



