10 NEW YORK STATE MUSEUM 



(group 3) and the occurrence of such forms as Ampyx and 

 Remopleurides in the limestone pebbles of groups 5 and 6 have 

 been a cause of no little concern to the writer, lest a failure to 

 separate the pebbles properly might cause a confusion of the 

 faunas, specially as both groups consist of black limestone peb- 

 bles; special attention has therefore been paid to the association 

 in the same pebbles of these new species with other well known 

 fossils; and in the descriptions the most important associates 

 have been mentioned. It has thus been found that nearly every 

 pebble of groups, 5, 6, 7 were characterized by a typical Trenton 

 form, removing thus the danger of a confusion with the Chazy 

 limestone. 



DESCRIPTION OF FAUNAS 



ANTHOZOA 



STREPTELASMA Hall 



Streptelasma corniculum Hall. Pal. N. Y. 1847. 1: C9 

 A number of specimens of a coral fully agreeing in external 

 and internal characters with Streptelasma corniculum, 

 were found in pebbles of black limestone of the Rysedorph hill 

 and Moordener kill conglomerates, as well as in the matrix of the 

 conglomerate at Schodack Landing. Several specimens repre- 

 sent the variety described by Hall as Streptelasma par- 

 vula. Streptelasma corniculum occurs in the Tren- 

 ton, from Baffin Land 1 over Canada and New York as far west as 

 Minnesota, but does not seem to go either above or below that 



formation. (Group 5) 



tetradium Dana 



Tetradium cellulosum Hall sp. 

 Phytopsis cellulosum Hall. Pal. N. Y. 1847. 1:39 

 This index fossil of the Lowville limestone was found in 

 boulders of light gray limestone in the Moordener kill conglom- 

 erate, which in their lithologic appearance show no difference 

 from the Lowville limestone of the Mohawk and Black river 

 valleys. (Group 4) 



i Schuchert. U. S. nat. mus. Proc. 1900. 22 :154. 



