AND COAL-MEASURES OF IOWA. 131 



Favosites scabra. Here also are loose sheets of shale, which have been washed from 

 the banks of the creek, and lie mixed with small boulders over the limestone. A 

 bed of coal a foot in thickness has been discovered in this neighbourhood. 



On Grand River, in the vicinity of Pisgah, nothing but drift is to be seen. Some 

 miles down the stream, however, near a mill-site, I was told by the Mormons that 

 a kind of " soapstone" could be seen at a low stage of water, which I suppose to be 

 an indurated argillaceous shale ; these deposits being popularly known by that 

 name in the West. This I was unable to examine in person : indisposition, from 

 fatigue and exposure, having brought on a relapse of intermittent fever, contracted 

 while exploring the Des Moines. 



The distances from Fort Des Moines to Pisgah are as follows : 



Miles. 



To the crossing of North River, ...... 10 



To Middle River, ...... 12 



To the South or Clanton Fork of Middle River, .... 2 



To Clanton's, ........ 2 



To Big Hollow, ....... 14 



To Forks of road leading to Bellevue, ..... 4 



To Pisgah, ........ 6 



Total distance, ....... 50 



On the route from Pisgah to Council Bluffs, I crossed Grand River, the Platte 

 Branch of Grand River, two branches of the Nodoway, A Hundred and Two 

 River, and the east, middle, and west branches of the Nishnabotna River. It was 

 only on this latter stream that any rocks were found in place. 



On the East Fork of the Nishnabotna, the following section was observed : 



1. Soft, brown sandstone, at an elevation of fifty feet. 



2. A light-buff limestone, containing Fusulina cylindrica, Bellerophon, allied to B. 

 Urii, an undetermined species of Cypricardia and Gervillia, at an elevation of 

 twenty-five feet. 



3. Limestone of irregular fracture, containing few or no fossils under the Fusu- 

 lina limestone. 



4. Compact limestone, one stratum of which is mottled with brown, in the bed 

 of the river.* 



A lighter-coloured gritstone is found in a grove, one mile east of the same stream. 

 On the main branch of the Nishnabotna, a close-textured, gray limestone occurs, 

 like that on the East Fork, containing casts of Bellerophon Urii. 



After crossing the Nishnabotna, no rocks appear in place until reaching the Mis- 

 souri River. A change can be perceived, however, in the character of the soil, 

 which becomes more argillaceous than it is between the forks of Grand River and 

 the branches of the Nodoway River. In dry weather, the roads, except in the low 

 places, become nearly as hard as if paved with rocks, and the wheel-tracks look as 

 smooth as if polished. 



* The intervening spaces between these beds are hidden from view. 



