Geological Problems in Muscatine County. 13 



demissa, Orthis iozuoisis, and Sfirifcra aspcra\ — 4, a consider- 

 able thickness of sandstones containing no fossils as far as ob- 

 served; — 5, arenaceous beds containing casts or impressions 

 of corals related to Cladopora, and impressions of what seem 

 to be immense masses of Stromatop>ora\ — 6, a bed of frag- 

 mentary materials interstratified with irregularly interrupted 

 fiexuous beds of shale and sandstone, varying greatly in thick- 

 ness and spread over the uneven and apparently eroded sur- 

 face of the underlying sandstone; — 7? lltixuous beds of shale, 

 with a bed of impure coal from two to three feet in thickness; 

 — 8, evenly bedded friable sandstone varying in color from 

 yellow to gray, and containing in some of its la3-ers numerous 

 impressions of Calamiies, Si^illaria and Lcpidodendon. 

 Casts of the stems of Lcpidodendon, apparently of the 

 species recognized by Owen as L. acitlcatiini, Sternberg, ^ 

 were observed more than nine inches in diameter. 



The beds 1-5 are of Devonian age and must all be referred to 

 the same period as the limestones at Buffalo and Pine Creek 

 Mills. Beds 6, 7 and 8 are of much later origin; they belong 

 to the Carboniferous period and were probably contempora- 

 neous with the Upper coal measures of southwestern Iowa. 



Practically the same succession of strata as seen in Robin- 

 son's Creek, may be observed in what is known as the rail- 

 road quarry at Montpelier. An immense quantity of stone 

 was taken out by the railway com pan v and used as riprapping 

 to protect the embankment from the wash of the river. The 

 magnitude of the work performed here ma}- be inferred from 

 the fact that the riprapping extends, sometimes for miles con- 

 tinuously, as far as Muscatine, a distance of sixteen miles. 

 The beds worked were Devonian sandstone, the equivalents 

 of 3, 4 and 5 of the section on Robinson's Creek. The 

 spirifer-bearing layer is here about two feet in thickness, it is 

 harder than at the localities on Robinson's Creek or on the 

 river above the mouth of Pine Creek, and it would seem to 



I Owen's Geological Survey of Wisconsin, Iowa and Minnesota, Table VI, 

 Figs. I, 2. 



