Northern end of main pit

Holocene glacial strata cover the eroded surface of the Iowa City Member of the Coralville Formation in this shot. This contact is known as an unconformity. The Holocene sediments are a few thousands of years old, while the limestones are 375 MILLION years old. A great expanse of geologic time is missing at this contact horizon.

Page: 6 of 6 (100%)