474 IOWA ACADEMY OF SCIENCE Vol. XXVI, 1919 



Carbonic section of the region. This is exactly the section which 

 recently we are in 'the habit of calling the Mississippian formation, 

 the adaptation of Winchell's name^'' of 1869. Being the name of a 

 strictly provincial series the policy of the United States Geological 

 Survey to elevate it to the continental dignity of an abstract time 

 unit of sub-periodic rank appears unavailing. 



In the interests of exact synonymy, of the proper appreciation of 

 the canons of priority, and of a just credit to the pioneer workers 

 in a particular provincial field it may be that we shall have to, in 

 the end, recognize for the early Carbonic section of the Mississippi 

 valley the terminology of Englemann and his co-workers, if we 

 finally find it really advisable to retain a definite geographic title 

 for what is really a time-division. By this line of action Louisian 

 would find satisfactory substitution for Mississippian ; and this title 

 would have priority over Winchell's name by twenty years. To be 

 sure, both terms have been used in varied senses. Even with the 

 latest tendency to establish a three-fold division of Early Carbonic 

 rocks in the Mississippi valley Louisian would appropriately take 

 precedence .over Mississippian as a serial title, for the median num- 

 ber. 



The severe restriction of the term St. Louis Limestone to the for- 

 mation generally known under that title today is probably due pri- 

 marily to the interpretation of Owen. As already intimated, in his 

 Report on the Geological Survey of Wisconsin, Iowa and Minne- 

 sota,^' published in 1852, he specifically designates the bed the 

 Concretionary Limestone, at the same time parallelling it with the 

 "Bedded Limestone of the City of St. Louis." 



At this time the Archimedes Limestones were regarded as the 

 same formation in place of three widely separated strata as subse- 

 quently proved to be the case. The present St. Louis formation was 

 thought to overlie it. In this connection, also, there was much con- 

 fusion existing concerning the Ferruginous Sandstone. The latter 

 was located at the bottom of the Coal Measures, and at the mouth 

 of the Missouri river it was above the St. Louis Limestone. Farther 

 south, near the mouth of the Ohio river, a lithologically similar 

 formation, now called the Aux Vases Sandstone, was erroneously 

 paralleled with the basal Coal Measures bed. For the honor of 

 discovering the true order of succession A. H. Worthen laid claim. 

 This worker, somewhat peeved at Prof. James Hall for first pub- 

 lishing correct details of the section without giving him especial 



"Proc. American Philos. Soc, Vol. XI, p. 79, 1869. 

 »'p. 92. 



