[Illustration: Cover Picture. View of the entrance to Calvin Coolidge State Forest Park. Photograph was taken looking north along State Highway 100A.] THE GEOLOGY OF CALVIN COOLIDGE STATE FOREST _By_ HARRY W. DODGE, JR. DEPARTMENT OF FORESTS AND PARKS Perry H. Merrill, _Director_ VERMONT DEVELOPMENT COMMISSION VERMONT GEOLOGICAL SURVEY Charles G. Doll, _State Geologist_ 1959 THE GEOLOGY OF CALVIN COOLIDGE STATE FOREST PARK _By_ HARRY W. DODGE, JR. INTRODUCTION Each summer hundreds of eager campers, picnickers, hikers and sportsmen visit the Pinney Hollow-Bradley Hill recreational area of the Calvin Coolidge State Forest Park. This area is located a few miles north of Plymouth, Vermont, and is easily reached via State Route 100A from either Plymouth or Bridgewater Corners (See index map of Vermont, geological map). The excellent camping and recreational facilities coupled with the natural scenic beauty of this region provide many visitors with an irresistible urge to return, summer after summer, to this same spot. This pamphlet is designed for all those who visit Coolidge Forest Park and especially for those who possess questioning minds and a general desire to learn more about the world around them. GEOLOGY Have you ever wondered why the present mountains and valleys are where they are and how and when they got there? Has the thought passed through your mind that the very rocks on which you stand or see nearby have a definite story to tell? The geologist not only wonders about such things, but through his training attempts to answer questions of this nature. His everyday job includes the reconstruction of ancient land and sea areas through a careful study of the rock record. He looks at the rock layers as you might the pages of a history book. The professional geologist, however, commands many basic geological principles and “tools of the trade” which permit him to read more accurately the records preserved in stone. First, the basic geological principles will be explained and you will be given the proper “tools” for your adventure. Then, you are invited to travel back through 550 million years of time to see just why Coolidge State Forest Park is as it is today and what it was like in the distant past. BASIC PRINCIPLES AND “TOOLS”