1
2
3
4
5
6
“...United States Dept. of the Interior...”
Book
7
Published 1950
“...United States Dept. of the Interior Division of Geography...”
Record Source:
Published Materials
Book
8
Record Source:
Published Materials
Book
9
“...United States Dept. of the interior Engineer office...”
Book
10
11
12
Published 1992
“...United States Dept. of the Interior Southwestern Pennsylvania Heritage Preservation Commission...”
Record Source:
Published Materials
Map
13
14
“...United States Dept. of the Interior...”
Book
15
Published 1950
“...United States Dept. of the Interior Division of Geography...”
Record Source:
Published Materials
Book
16
Published 1992
“...United States Dept. of the Interior Southwestern Pennsylvania Heritage Preservation Commission...”
Record Source:
Published Materials
Book