Borings (4 of 7)

Concrete borings No.  22-10 1 and 17-10-1, Electronic reproduction of photograph.  The Mackinac Bridge 1954 - 1958. Mackinac Bridge Authority
Abstract/Description: Concrete borings No. 22-10 1 and 17-10-1
Subject(s): Bridges--Design and construction
St. Ignace (Mich.)
Mackinaw City (Mich.)
Mackinac Bridge (Mich.)
Date Created: 1955 (approximate)