THE EURYPTERIDA OF NEW YORK Tog 
salt.’ Recent writers’? have held that such thicknesses of salt can not be 
explained by the desiccation of a sea enclosed by land barriers in distinction 
from bars. The salt of the Retsof mine would require the desiccation of a 
sea 1750 feet deep, and this is irreconcilable with the shallow water con- 
ditions of the Salina beds evidenced by the frequent sun cracks in the 
dolomites and waterlimes of the formation. 
There is no doubt that the culminant salt pan condition of the Salina 
period with its heavy precipitation of salt, implies an arid climate. There 
is also evidence indicating the persistence of these desert conditions through- 
out the Salina period and at the time when the eurypterid-bearing sediments 
were deposited. This evidence is found in (1) the scarcity of carbonaceous: 
matter in the Salina beds, (2) the prevalence of dolomites and waterlimes. 
The Salina beds are notably free from carbonaceous matter when com- 
pared with the underlying Niagaran and overlying Helderbergian beds. 
This may be partly due to the absence of such decaying marine organisms 
as furnished the bitumen with which part of the underlying Guelph 
dolomite is saturated, but it is also an indication of the absence of 
vegetation on the adjoining land. This becomes especially manifest if 
it is considered that the Salina sea was almost entirely surrounded by land, 
and that, as the frequent sun cracks in the waterlimes of central New York 
demonstrate, the shore was nowhere very distant. Several authors, as 
1The section is as follows: 
. Feet 
6 Onondaga 
Oriskany 
68 Limestone (Lower Helderberg + Manlius) 
47, Gypsum 
63 Limestone 
140 Shale and limestone 
89 Shale 
12 Limestone 
32 Shale 
22 Salt 
30 Shale and limestone 
58 Salt 
Shale 
7 Kemp, Handbook of Rocks, 1904, p. 106. 
