The Geology of Sebago Lake State Park

Introduction

This pamphlet has been prepared for the use of tourists and campers who are interested in learning the origin of the scenery around them. The finest appreciation of scenic beauty comes through understanding how the landscape took its present form, and there is no better opportunity to gain some understanding of Earth history than when the evidence is available at every glance. Sebago Lake State Park (Figure 1) is not a place of awe-inspiring mountains or canyons, but within its limits there is abundant evidence of a fascinating history. We hope that by reading this pamphlet and visiting the places described, you will begin to see how geologists are able to interpret Earth history, and we further hope that some of the principles of interpretation illustrated here will be useful to you as you travel through other regions.

Sebago Lake lies on the boundary between two geographic regions. Southeast of the lake is a coastal plain about 15 miles wide, with many low rocky ridges separated by broad valleys. The relief (the difference in altitude between valley floors and adjacent hill tops) on the coastal plain is generally less than 300 feet. Northwest of the lake is a rugged upland region in which the maximum relief increases toward the northwest from about 1000 feet near Sebago Lake to more than 4000 feet in the heart of the White Mountains. Mount Washington, the highest peak in the northeastern United States (6,288 feet) is just 44 airline miles northwest of Sebago Lake State Park.

Sebago Lake has a surface area of 44.8 square miles, and is the second largest lake in the State of Maine, exceeded only by Moosehead Lake. The surface of the lake is normally at an altitude of slightly more than 270 feet above sea level, although the surface level varies according to the amount of annual precipitation. The lake has a maximum depth of 316 feet, at a point about 4 miles south of the State Park. It is interesting to note that the deepest part of the lake is actually more than 40 feet below sea level.

Sebago Lake State Park occupies an area of 1296 acres at the northern end of the lake, divided into two nearly-equal halves by the Songo River. Most of the sandy plains in the park lie less than 30 feet above lake level, but scattered rocky hills are somewhat higher. The highest point in the State Park is the crest of a hill on the western boundary of the park at an altitude of 499 feet. A trail leads to this hill top from the campground road.

Introduction Geologic History Features of Interest Geologic Map (pdf)

Last updated on January 11, 2008

Contents

The Geology of Sebago Lake State Park

Introduction