The geologic story of the park consists of two distinct chapters: one recorded in the bedrock, which ranges from 400 to 7 million years in age, and a second much younger story written in the surficial sediments whose ages with few exceptions range from ca. 20,000 years ago to the present.
The geologic story of the park consists of two distinct chapters: one recorded in the bedrock, which ranges from 400 to 7 million years in age, and a ...
