106 NEW YORK STATE MUSEUM 
deposits of the Salina formation and the absence of fossils in the middle 
Salina beds (Vernon, Camillus shale) which were early ascribed to “ salt 
pan ’’ conditions in the Salina sea. The authors have pointed out in 
Memoir 5 [Guelph Fauna of New York, p. 117] that the preceding Guelph was 
a distinct phase in the development of the vast Niagara coral sea into the 
desiccating, more or less inclosed sea of the Salina stage, the fauna of the. 
Guelph already exhibiting characters suggestive of the increased salinity — 
of the sea. The cycle of events leading to the culmination and decline 
of the Salina sea has been expressed by Hartnagel in the appended dia- 
gram and described as follows: 
DECREASING A Niagara—Guelph . Cobleskill 
SALINITY B fauna 
Cc Waterlime 
| with Eurypterus 
Gypseous 
D shales 
Beds of Salina 
rock salt 
INCREASING D Gypseous 
SALINITY shales 
C Pittsford shale 
with Eurypterus 
B Guelph 
fauna 
Niagaran 
A Niagara 
fauna 
a 
With the ever increasing salinity of the waters the Guelph fauna 
retreats, and next in the black Pittsford shale at the base of the Salina 
there occur Eurypteri, and with them constantly associated a species of 
Lingula. With the retreat of this fauna we find, as physical changes went 
on, deposits of gypseous shale and later the salt beds. The deposition of 
these great beds of rock salt marks the turning point in this cycle,... 
beds of gypsum were again deposited, but never again were the conditions 
favorable for the deposition of extensive beds of rock salt. Following the 
gypsum beds, we have the Salina waterlime with its splendid Eurypterus 
- fauna, and associated with the Eurypterus is a species of Lingula simi- 
