184 



Natural History Bulletin. 



Section on West Side of Wapsipinicon River, About 



One-Quarter Mile Below the Dam, 



AT Littleton, Iowa. 



7. Yellow argillaceous shales with 

 large Sirofhodonta dcmissa, a very 

 coarsely ribbed Atrypa j-cticularis, 

 a small Cyrtina hamjltonensis, Stri- 

 ato-pora 7'itgvsa, Orthis stthorbicii- 

 laris related to O. inipressa, Tere- 

 brahila sp?, a small Rhynchonella^ 

 Athyris vittata^ rare, a well mark- 

 ed variety of Spirifera parryana, 

 probably a new species, etc. 



6. A bed of indurated shales, som.e- 

 what barren of fossils. 



5. Compact reef of Acervularia david- 

 soni, with many species of Favo- 

 sitcs, a Chonopkylhim, Cladopora 

 proJifcra and C. pahnata. 



4. Rather hard, dark granular lime- 

 stone, with Spirifera parryana^ 

 large, long -hinged, Strophodonta 

 deinissa, Alrypa reticularis. 



3. Thin la3'er of yellow shaly lime- 

 stone, with JVewherria j'okannis, 

 Tercbraiula roiuingeri and Penta- 

 merclla arata. 



_ _ _ 2. 



I. 



Beds containing Cystipkyllit-m, Acer- 

 vjdaria prqfiinda, a few specimens 

 of Spirifera pcnnata Owen. 



Limestone with CystipkyUum amer- 

 icannni. 



LEVEL OF WATER IN RIVER. 



