144 STUART WELLE R 



45. Proetus sp. undet. 



46. Spirophyton sp. undet. These fucoid markings are abundant 

 everywhere in the sandstone, and with the worm borings are the 

 only fossils which are always recognizable in this formation. 



When the description of the Northview fauna was published 

 no differentiation of the faunas of the "yellow sandstone" at 

 Burlington was possible. Since that time, however, a study of 

 the type collections from that locality has shown that two quite 

 distinct yellow sandstone faunas occur. 1 The lower is charac- 

 terized by Chonopectus fischeri N. & P., and the bed containing it, 

 bed No. 2, has been called the Chonopectus sandstone. The 

 upper yellow sandstone is characterized by the presence of Per- 

 ?wpecten, Promacrus, and Palaeoneilo, genera which are wanting 

 from the Chonopectus fauna. These same genera, however, are 

 among the most characteristic forms of the Northview sandstone, 

 and all of them are also present in the fauna of the typical 

 Chouteau limestone of central Missouri. The faunas of ihe 

 Northview sandstone and of the upper yellow sandstone at Bur- 

 lington may be considered as analagous, and they may without 

 hesitation be considered as one facies of the upper Kinderhook 

 or Chouteau fauna. 



The Northview shales are usually quite barren of fossils, but 

 at a few localities they are abundant. They are mostly brachio- 

 pods and corals, but no complete list of species can be given in 

 this place. The collections in Walker Museum contain only a 

 few specimens from this bed near Bolivar in Polk county, the 

 species represented being Atliyris lamellosa, Reticularia coopere?isis, 

 and Rhipidomella burlingtonejisis. These species are all present 

 in the fauna of the typical Chouteau limestone elsewhere. 



Pierson limestone. — This is a fine-grained, buff colored, gritty 

 limestone having a maximum thickness, according to Shepard, 2 

 of thirty feet, being the formation designated by him as 'the 

 Chouteau limestone. In view of what has already been written 

 in regard to the faunas of the Sac limestone and the Northview 

 sandstone, it will be recognized that the formation is by no 



'Iowa Geol. Surv., Vol. X, p. 79. 2 Loc. cit., p. S3. 



