Iowa Heritage Digital Collections
State Library of Iowa

Browse Items (748 total) for Calvin Geological Photographs

Man in front of section of Maquoketa shales, Graf, Iowa, late 1890s or early 1900s

Man in front of section of Maquoketa shales, Graf, Iowa, late 1890s or early 1900s

Located west of Graf.
Shearing, Specht's Ferry, Iowa, late 1890s or early 1900s

Shearing, Specht's Ferry, Iowa, late 1890s or early 1900s

Overlying Saint Croix sandstone, fold and dip shows beyond Bridge, dark line above railway marking the base of the Oneota, Quandahl, Iowa, late 1890s or early 1900s

Overlying Saint Croix sandstone, fold and dip shows beyond Bridge, dark line above railway marking the base of the Oneota, Quandahl, Iowa, late 1890s or early 1900s

Sixty foot high bluff of Oneota (massive above) with cherty partings at base, Iowa, late 1890s or early 1900s

Sixty foot high bluff of Oneota (massive above) with cherty partings at base, Iowa, late 1890s or early 1900s

Located in the R.W. Section 16, S.W. gr., N.E. 1/4.
Cliff of Trenton Limestone on the Oneota River, Bluffton, Iowa, late 1890s or early 1900s

Cliff of Trenton Limestone on the Oneota River, Bluffton, Iowa, late 1890s or early 1900s

Cliff of Trenton Limestone in Cold Water Spring State Preserve, Bluffton, Iowa, late 1890s or early 1900s

Cliff of Trenton Limestone in Cold Water Spring State Preserve, Bluffton, Iowa, late 1890s or early 1900s

Plymouth Rock above the Iowa river, Bluffton, Iowa, late 1890s or early 1900s

Plymouth Rock above the Iowa river, Bluffton, Iowa, late 1890s or early 1900s

Railroad cut through Maquoketa Shales, Graf, Iowa, late 1890s or early 1900s

Railroad cut through Maquoketa Shales, Graf, Iowa, late 1890s or early 1900s

Located north of Graf.
Cliff above Rawson's Mill. The thick ledge at the summit is Niagara limestone. Iowa, late 1890s or early 1900s

Cliff above Rawson's Mill. The thick ledge at the summit is Niagara limestone. Iowa, late 1890s or early 1900s

The height from the level of the stream to the line of contact is 94 feet.
Bluff on Upper Iowa River (formerly Oneota River), Saint Croix capped by Oneota, height 300 ft. plus, Iowa, late 1890s or early 1900s

Bluff on Upper Iowa River (formerly Oneota River), Saint Croix capped by Oneota, height 300 ft. plus, Iowa, late 1890s or early 1900s

Bear Creek, near the south of Allamakee Co.
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