No. 3.— A REVIEW OF THE EVIDENCE FOR THE 
TACONIC REVOLUTION. 
BY THOMAS H. CLARK. 
Contents. 
Introduction 135 
Nova Scotia 137 
New Brunswick and Eastern Quebec 140 
Central New England 150 
Montreal and Vicinity 152 
Hudson Valley 153 
Shawangunk Mountain 150 
The Taconics and the Green Mountains 157 
Crystalline Rocks of New York City, New Jersey Highlands, and 
Southward 159 
Conclusion 161 
Introduction. 
This paper proposes to review the evidence for a long-accepted 
statement, first enunciated by Dana in 1863, and repeated in 
each subsequent edition of the Manual, that the close of the 
Ordovician was attended by uplift and folding in eastern North 
America, and to show how little evidence has been found in 
support of this view. This has necessitated an examination of 
the literature on this subject, the results of which are embodied 
in the following pages. 
In the first edition of Dana's justly celebrated Manual of 
Geology, page 227, we find the following statement. "In 
British America, near Gaspe, on the Bay of St. Lawrence, ac- 
cording to Logan, the Lower Silurian lies in tilted strata beneath 
beds of the Upper Silurian, showing that an upturning had 
occurred before these superior beds were formed. Similar facts 
have been observed at the eastern base of the Green Mountains, 
where limestones of Upper Silurian and Devonian age rest un- 
135 
