8 NEW YORK STATE MUSEUM 
Columbia University, through Profs. A. W. Grabau and Jesse E. Hyde 
Museum of Comparative Zoology, Cambridge, through Dr Samuel 
Henshaw 
The Peter Redpath Museum, McGill University, through Dr Frank 
D. Adams 
Geological Survey of Canada, through Dr Percy E. Raymond 
Dr E. M. Kindle, Washington 
Prof. Stuart Weller, Chicago 
Prof. Gilbert van Ingen, Princeton 
Dr Mark E. Reed, Buftalo 
Mr Irving P. Bishop, Buffalo 
Dr August F. Foerste, Dayton, Ohio 
Mr Fred Braun, Brooklyn 
The illustrations in the work are from drawings skilfully rendered 
by George S. Barkentin, many of them, especially the restorations and 
stages of immature growth, based on Dr Ruedemann’s sketches and 
camera drawings. 
2 of of 
The eurypterid colonies of the New York Siluric are very distinctly. 
localized and of them we know two at the bottom of the Salina series or 
beneath the salt beds and two at the top of the series. These colonies 
were doubtless in part breeding pools in brackish waters, partly more 
open basins, restricted in extent by the limitations of favorable physical 
conditions. 
Colony O, or the Otisville basin lying far eastward of the rest and on the 
borders of the Appalachian region, is embedded in an almost unlimited 
repetition of thin black shale between layers of heavy sandstone of the 
Shawangunk formation (Salina stage). In the construction of railroad 
improvements the rock wall here was broken down for ballast and while 
this work was in progress the eurypterid remains were detected by 
Dr Ruedemann. From this time on until the completion of the con- 
struction work referred to, Mr H. C. Wardell was almost continuously 
