554 C. SCHUCHERT PALEOGEOGRAPHY OE NORTH AMERICA 



two eastern seas. In the Saint Lawrence sea there is almost no evidence 

 for the presence of Meramecian deposits and none at all for the Ches- 

 terian. 



Mississippian sea. — The best general account of the successive sedi- 

 ments of this sea in the area of its longest development — that is, western 

 Kentucky and southwestern Illinois — is that of Ulrich. 167 This succes- 

 sion is given in the column "Mississippi valley east of Missouria," in the 

 table of formations belonging to this period. 



The Upper Warsaw 168 (— Salem or Spergen), a rather limited forma- 

 tion, introduces the Meramecian, and many of its fossils are continued 

 into the higher horizons. Hall described the fauna in 1858, 169 the more 

 characteristic forms being Zaphrentis spinulifera, Archimedes wortheni, 

 Pentremites Tconinchiana, Spirifer subcardiiformis, S. lateralis, S. sub- 

 equalis, and Bellerophon sublcevis. 



The Spergen oolitic limestone is noted for its dwarfed fauna, preserved 

 in oolites. It was first described by Hall ; later by Whitfield. 170 The ear- 

 liest appearance of this fauna was in the Upper Warsaw; it became typi- 

 cal and enlarged in the Spergen ; its third occurrence was in the Fredonia 

 (35 species of the second occurrence are here represented), and for the 

 fourth time it appeared in the Tribune (40 of the 70 original species are 

 present). Ulrich has recently discovered the same fauna, greatly dimin- 

 ished, in the Pottsville, and its existence in the Montana-Idaho region,, 

 described by Meek, should probably be attributed to the same age. 



The Saint Louis limestone is usually heavy bedded and gray, with 

 much siliceous matter that is liberated as chert. The guide fossils are 

 Lithostrotion ( ?) canadense and L. (?) proliferum. Ulrich states that 

 the columella of these forms is not styliform, as in Lithostrotion, and 

 that the species are more nearly allied to Lonsdaleia. Castelnau was the 

 first to describe these corals. His Astrwa mamillaris is identified as 

 Fischer's species, and was obtained on the Ohio river, in the state of 

 Illinois. This is the form that is usually known as Lithostrotion cana- 

 dense. Castelnau's Axinura canadensis is the form now called L. pro- 

 liferum; it was collected on the shore of lake Saint Claire, Michigan, this 

 fact leading him to call it canadensis. Both of these corals are figured 

 and described by Eominger, who reports them as occurring at Wildfowl 

 bay, Bellevue, and Grand Eapids, Michigan. Under these circumstances 

 the coral now called L. proliferum will in future have to be known as 



167 Ulrich : Professional Paper no. 36, U. S. Geological Survey, 1905. 

 188 Weller : Bull. 8, Illinois Geological Survey, 1907, p. 83. 



169 Hall : Geological Survey of Iowa, Paleontology, part ii. 



170 Whitfield : Bull. American Museum of Natural History, 1882 ; republished and ex- 

 tended by Hall in Indiana Geological and Natural History Survey, 1882. 



