16 NEW YORK STATE MTSEUM 



black liinestom* of KvsedtJrph hill. Tlu' spocimeu Im smaller by 

 one half than the averag^e specimens of P h o 1 i d o p s 

 t r e n t o n e u « i s ; but, it beinj; the only specimen found, 

 a comparison with the variety 1* h o 1 i d o p s t r e n t o n e n s i e 

 var. m i n o r AN'inchell and Schuchert, from the base of the 

 Cralena limestone at St Paul, is excluded. Judji:ing from the 

 drawing given of that form, the Rysedorph hill specimen shows 

 the same slight truncation as the western form, which becomes 

 more emphasized in IMi o 1 i d o p s s u b t r u n c a t u s. 



Hall does not give the exact horizon of his species, which was 

 secured at Middleville, and Dr White and Prof. Prosser did not 

 find the fossil in the e^ections of Trenton Falls and other locali- 

 ties along the West Canada cirek; the western variety occurs 

 in the Black river and lower Trenton beds. (Group 5j 



RAFiNESQuiNA 11 all iVi Clarke 



Rafinesquina alternata (Emmons) Hall & Clai'ke 



Leptaeua alternata Emmons. Geol. of N. Y. Rep't on 

 second district. 1842. p. 395 



PI. 2, fig. 1 

 Many pebbles of the gray crystalline limestone of Rysedorph 

 hill are filled to the exclusion of other fossils with very large speci- 

 mens of Rafinesquina alter n a t a . The extreme size 

 of a great number of specimens, combined with a remarkable 

 extension of the cardinal region, constitutes a striking variation 

 from the type, which becomes more emphasized in such Lorraine 

 f onns as Rafinesquina alternata 1 o x o r h y t i s 

 Meek. Numerous other specimens are remarkable for the 

 strong oblique corrugation of their cardinal regions. Several 

 specimens of great gibbosity and thick shell were also found in 

 the compact reddish gray, ostracode limestone of Rysedorph hill. 

 R a f i n e s q u i II <i alternata is also of frequent occuri^ence 

 in the matrix of the conglomerate at the Moordener kill and at 

 Schodack Landing. This form ranges from the Chazy to the 

 Tx»rraine beds and extends from Canada to Minnesota and 

 Manitoba. (Group 7) 



