CONTRIBUTIONS TO THE GEOLOGY OF MAINE. 
PART I, THE PALEOZOIC FAUNAS OF MAINE. 
By Henry S. Williams. 
CLASSIFICATION OF THF PALFOZOIC TERRANES OF 
AROOSTOOK COUNTY. 
Recent investigation of the rocks of the northern part of Aroostook 
County has brought to light a few facts regarding the stratigraphic 
terranes, which may be stated with some degree of precision. 
There are a few well-marked groups of rocks which are distinguish- 
able by their lithologic characters, and the relative age of which is 
determined by their contained fossils. The order which the present 
knowledge of the faunas seems to indicate is as follows: 
9. Mapleton sandstone . 
8. Moose River sandstone. . } = Devonian. 
7. Chapman sandstone . . . 
6. Square Lake limestone. 
5. Ashland limestone 
4. Ashland shales 
3. Sheridan sandstone 
2. Graptolite shales 
1. Aroostook limestone... 
Silurian. 
Below the Aroostook limestones are slates, which it is believed are of 
Cambrian age, but positive evidence of the age is wanting. 
The lower seven belong to the Silurian; the upper two to the Devo- 
nian. The paleontologic evidence is clear in placing 1-5 below the 
Lower Helderberg horizon of the New York series. 
The Aroostook limestone, on both stratigraphic and paleontologic 
grounds, is believed to be older than any other of the terranes men- 
tioned in this list. 
The Ashland limestone, Ashland shales, and Sheridan sandstone are 
faunally closely associated, and belong together as the representatives 
of the Clinton-Niagara of the New York standard. 
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