ISBN-13: 9781492359326 / Angielski / Miękka / 2013 / 58 str.
ISBN-13: 9781492359326 / Angielski / Miękka / 2013 / 58 str.
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.