REPORT OF COMMITTEE ON PHOTOGRAPHS 477 



1856 (39). Leclaire limestone near Massillon, Iowa. Illustrating the breaking 



down of cliffs along joint planes. 



1857 (40). Ferruginous stains. Slab of Anamosa limestone, Leclaire stage of 



Niagara, from Mount Vernon quarry, Iowa. 



1858 (41). Bieler's quarry. Cedar Valley, Iowa, showing horizontal and even bed- 



ding of Anamosa stone. Leclaire stage of the Niagara. 



1859 (42). Cliff at Kenwood, Iowa. The lower 8 of feet Otis limestone, the basal 



member of the Devonian Series in Iowa. Above the Otis is seen the 

 Independence shale with associated limestones. Iowa Geological Sur- 

 vey, volume iv, pages 142, 143. 



1860 (43). Kenwood bluff on Indian creek, Kenwood, Iowa. Fayette breccia at 



highest point. Otis limestone. Iowa Geological Snrvey, volume iv, 

 pages 142, 143. 



1861 (44). Independence shale. Linn, Linn county, Iowa. The light-colored clay 



shown in this landslip is the only known fossiliferous outcrop of these 

 shales. Fayette breccia on either side. 



1862 (45). The Lower Davenport beds. Devonian. Mouth of Duck creek, Scott 



county, Iowa. Reference, Geology of Scott county, Iowa Geological 

 Survey, volume ix. 



1863 (46). Brecciated beds of Lower Davenport limestone. Rock Island, northwest 



shore, Illinois. A flexed and broken fragment. 



1864 (47). Breccia in Lower Davenport beds. Rock Island, Illinois. 



1865 (48). Breccia in Lower Davenport beds. Rock Island, Illinois. Initial flex- 



ures. 



1866 (49). Breccia, Linn, Linn county, Iowa. General view. This brecciated 



horizon, known as "the Fayette breccias," involves the following 

 members of the Devonian series : Cedar Valley stage, Spirifer pen- 

 natus beds ; Wapsipinicon stage. Upper Devonian beds. Lower Daven- 

 port beds ; Independence shales. Iowa Geological Survey, volume 

 iv, pages 157-166. 



1867 (50). Breccia, Linn, Linn county. Iowa. Lowest phase, natural size. Iowa 



Geological Survey, volume iv, pages 157-166. 



1868 (51).. Breccia, Linn, Linn county, Iowa. Second phase. Chiefly fragments 



of Lower Davenport limestone. Iowa Geological Survey, volume iv, 

 pages 157-166. 



1869 (52). Breccia, Linn, Linn county, Iowa. Close view. Complex brecciation 



in large fragments. Iowa Geological Survey, volume iv, pages 1 57-166. 

 • 1870 (53). Breccia, Linn, Linn county, Iowa. Illustrating differential weathering 

 of breccia, largely made up of Independence shales (buff, Kenwood 

 phase), forming abundant talus and breccia formed of numerous 

 fragments of Lower Davenport limestone, with sparse matrix. Iowa 

 Geological Survey, volume iv, pages 157-166. 



1871 (54). Breccia, Linn, south end of cut. Showing tilting. 



1872 (55). Breccia, Linn, Iowa. Showing large blocks of Upper Davenport lime- 



stone retaining approximately their plane of deposition. The sides 

 of these tilted blocks are usually affected with slickensides. 



1873 (56). Breccia, Linn, Linn county, Iowa. Close view. Iowa Geological Survey 



volume iv, pages 157-166. 



