502 University of Kansas Geological Survey. 



THE FORT PIERRE FAUNA. 



The Fort Pierre area of Kansas has not been productive of a 

 very great number or diversity of invertebrate forms. Fossils 

 were collected in an early day from a Fort Pierre outcrop on 

 Butte creek, by Prof. B. F. Mudge, and, later on, some speci- 

 mens were collected from the same locality by Prof. S. W. Wil- 

 liston. Fort Pierre fossils were collected also by Judge West, 

 Professor Williston and Mr. Cooper from the Fort Pierre shales 

 on the North Fork of the Smoky Hill river, near McAllaster, in 

 Wallace county. But no very extensive outcrops of the Fort 

 Pierre formation occur in Kansas except in Cheyenne county, 

 and these outcrops were thought to be barren until recently. In 

 the summer of 1895 I collected a few fossils from the Cherry 

 creek and Arickaree outcrops, in the northern part of Cheyenne 

 county. These fossils were determined through the kindness of 

 Mr. T. W. Stanton, of the United States Geological Survey. In 

 the summer following, in company with Prof. H. J. Harnley, of 

 McPherson, I again visited the Arickaree outcrops, and an out- 

 crop in Rawlins county, a few miles north of At wood, and se- 

 cured additional forms. 



The form which occurs most abundantly in the Fort Pierre of 

 Kansas is BacuUtcs ovatus; but it is not the most characteristic 

 one, as it is also found in the Fox Hills formation. Lucina oc- 

 cidentalism one of its characteristic forms, is abundant in one 

 Arickaree horizon. Both of these fossils occur free in the 

 shales, as do a few other forms, but many of the Fort Pierre fos- 

 sils are imbedded in argillaceous nodules, which are scattered 

 throughout the shale beds. 



All told, the Fort Pierre formation in Kansas has furnished 

 fifteen species, none of which are new to science. It is more 

 than probable that a careful examination of the outcrops in the 

 localities above mentioned will reveal many of the hundred or 

 more species which have been described from this formation in 



