The landscape of Scripture Rocks Park was largely shaped during the ice age 24,000 to 12,000 years ago, when continental glaciers nearly 2 miles thick covered most of Canada and portions of the northern United States. The glacier did not reach Brookville, but the glacial front advanced within 50 miles northwest of here. Because of the cold climate, northwestern Pennsylvania was much like northern Alaska is today, and below a certain depth the ground remained frozen throughout the year. Ice penetrated natural fissures in the underlying bedrock, and over thousands of years the expanding ice forced large boulders free from exposed cliffs. During warmer summer months, the ground surface thawed and became saturated by summer rains, and muddy soil, rocks, and boulders slowly oozed down hillslopes over the frozen layers of soil. The boulders carved by Douglas Stahlman are remnants of this ice age landscape.