6 NEW YORK STATE MUSEUM 
of specific and generic differences, and the study of the habitudes of these 
animals. Notwithstanding, as early as 1895, I began the assemblage of 
materials looking specially to a revision of the New York and American 
eurypterid faunas. The collections of the State Museum were already 
pretty well supplied with representatives from the well known localities at 
Buffalo and in Herkimer county and now these collections: have been 
vastly amplified, first by repeated acquisitions from the Herkimer county 
localities during the past 15 years, again by the close study of all outcrops 
of the Eurypterus beds along the line between Herkimer county and 
Buffalo which has progressed in connection with the field work in areal 
geology, then by the courtesy of the trustees of the Buffalo Society cf 
Natural Sciences who in 1898, by special vote, placed at my disposal the 
extraordinary assemblage of specimens from the Buffalo cement quarries 
which is known, from the name of its principal contributor, as the Lewis 
J. Bennett Collection. Soon thereafter followed the discovery of the 
Eurypterus-bearing black shales at Pittsford, Monroe co., which were. 
brought to light by the work of enlargément of the Erie canal in 1895, the 
species of which were described in our reports by Mr Clifton J. Sarle 
from material now in possession of the State Museum. To this notable 
addition to our knowledge has been added in years still more recent the 
new fauna in the dark shales of the Shawangunk grit at Otisville, Orange 
co., an assemblage of eurypterids remarkable for its profusion of immature 
growth stages; this fauna lying far to the east of all previously known 
occurrences of these creatures, was described in a preliminary way by 
the writer. Still more recently, indeed since the preparation of this book was 
believed to be completed, the field investigations of Dr Ruedemann have 
brought to light a large and new fauna in the Lower Siluric (Frankfort) 
shale rather widely disseminated in the lower Mohawk valley and this 
constitutes the very earliest assemblage of these merostomes in conditions 
which indicate that they formed a colony of long local duration. 
The collections which have thus been brought together from the productive 
localities mentioned for the preparation of the present treatise have been 
