12 Natural History Bulletin. 



Chemung; much less are they Lower Carboniferous or Kin- 

 derhook. 



Owen gives a recognizable figure of Spirifera parryana as 

 it occurs with the shell preserved in the Hamilton limestones 

 along Pine Creek, and another figure of a cast of the same 

 species as it occurs in the overlying sandstones, i Both 

 forms are described as Spirifera eiiruteines^ but it is in- 

 teresting to note that the specific identit}'- of the two forms 

 is distinctly recognized, and that furthermore the beds con- 

 taining them are referred to the same period. 



No Kinderhook or Sub-carboniferous of any kind has been 

 observed by the writer in the region about Pine Creek in 

 Muscatine county. A very complete section of the rocks 

 of the region may be studied in the bed and banks of Robin- 

 son's Creek, a small stream emptying into the Mississippi a 

 short distance below Montpeher. Near the mouth of the 

 creek is the ledge of limestone already mentioned as exposed 

 at low water, and extending out into the river for more than a 

 hundred yards. This limestone is the same as that found at 

 Hanson's Quarrj^, Pine Creek Mills and many other points, 

 and is characterized b}^ the presence among others of the fol- 

 lowing fossil species: Spirifera -parryana, S. aspcra~Atrypa 

 reticularis, and Athyris vittata. Following up tiie channel of 

 Robinson's Creek we find, — i, beds of arenaceous shale with 

 some thin beds of limestone, containing branching polyzoa, 

 Atrypa reticularis, Strofhodonta demissa, very large forms, and 

 Orthis iozuensis;^ — 2, argillaceous shale only a few feet in 

 thickness and containing no fossils; — 3, layers of sandstone 

 among which is a bed about 14 inches in thickness containing 

 casts of Spirifera parryana, (5". capax) with which are 

 associated either in the same bed or in adjacent beds both 

 above and below, casts of Atrypa reticularis, Strophodonta 



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

 III, Figs. 2 and 6. 



2 No opportunity has yet been found to measure the thickness of the several 

 members of the section. 



