WILLIAMS.] 
THE ASHLAND SHALE. 
51 
Fauna of 1098 K °2. 
1. Orthothetes subplanus. 
2. Strophomena rhomboidalis. 
3. Stropheodonta perplana Billings. 
4. Orthis cf. elegantula. 
5. Spirifer bicostatus. 
6. Brachiopods, several undetermined 
species. 
7. Corals, several species. 
8. Crinoid stems. 
The Ashland shales, the Sheridan sandstone, and the Ashland lime- 
stone contain faunas of the Eosilurian, and from the evidence of 
structure already collected it is difficult to tell their exact relationship 
to one another. The writer's interpretation, with his present knowl- 
edge of the facts, is that the shales are older than the limestones, and 
that the Sheridan sandstones are of the same age as the shales. 
The disturbances which occurred in the ash beds and the associated 
Sheridan sandstone may also account for the fragmental condition of 
the Ashland limestone. If so, it is necessary to consider the limestone 
as already consolidated. This might have been the case and still the 
difference in age might be very slight, geologically speaking, for the 
consolidation of a coral reef deposit, though it might take centuries, 
does not require long geologic periods. 
In case the volcanic disturbances took place during the general 
Niagara time, the faunas and the condition of the several kinds of 
rock and their irregular relations may be rationally accounted for. 
In the faunas themselves there is clear evidence for the separation of 
the Square Lake fauna from those now under consideration. The 
Square Lake fauna is clearly equivalent to the Lower Helderberg of 
the New York series, and nearly to the "Delthyris Shaly limestone" 
part of it. The Ashland limestone, Ashland shale, and Sheridan sand- 
stone faunas are all older and may be correlated more closely with the 
Niagara of the New York series. 
It is to be observed, however, that the Sheridan sandstone faunas 
combine species of typical Niagara or even Clinton stages of New 
York with other species not found in that region below the Lower 
Helderberg. We may cite, for instance, Cypricardinia lamellosa and 
Phacops logani. Not only these, but closely allied species are found 
in the two faunas. 
In New Sweden, on the Olivenbaum farm (1096 H), a fine-grained 
shale, calcareous, but with enough siliceous grains to preserve the 
consistency of the rock after the lime is leached out, contains numer- 
ous crinoid stems, and among them are recognized plates of Caryocri- 
mis omatus, which determine the age to be that of the Clinton or 
Niagara of New York. For the present these may be referred to the 
Ashland shales. 
