Core samples from Mackinac Bridge (3 of 3)

Ass of the pier sites had to have core samples made for geological testing and study.  These are some of those specimens. The hardpan caused much difficulty., Electronic reproduction of photograph.  The Mackinac Bridge 1954 - 1958. Mackinac Bridge Authority
Abstract/Description: Ass of the pier sites had to have core samples made for geological testing and study. These are some of those specimens. The hardpan caused much difficulty.
Subject(s): Bridges--Design and construction
St. Ignace (Mich.)
Mackinaw City (Mich.)
Mackinac Bridge (Mich.)
Date Created: 1954 (approximate)