DELIMITATION OF THE ST. LOUIS 475 



credit for pointing out the situation stated^'^ that he unravelled the 

 puzzle as early as the spring of 1853, while assistant on the Illinois 

 survey, although he could not then publish the facts. 



It is probable that Hall, while state geologist of Iowa, gathered 

 his facts on this subject from numerous sources, and that Worthen 

 was only one out of many persons with whom he talked over mat- 

 ters. Moreover, at the very time when Worthen, in company with 

 Hall, visited the Chester locality the triple nature of the Archimedes 

 Limestone was being widely discussed, and doubt was already being 

 thrown upon the generally accepted interpretation. Otherwise it 

 is difficult to understand just why Dr. Norwood, the State Geologist 

 of Illinois, should especially charge his assistant Worthen with the 

 duty of determining the relations of the St. Louis Limestone as 

 recently restricted and the Ferruginous Sandstone. ^^ 



Although Swallow-" adhered to the old idea of the location of 

 the St. Louis Limestone (restricted) above the Chester beds, Shu- 

 mard, in the county reports made at the same time, but the publica- 

 tion of which was held up by the Civil War for fifteen years, clearly 

 recognized the true sequence. Furthermore, in the South, in Ste. 

 Genevieve county, he subdivided the section between the first and 

 third Archimedes limestones (Keokuk and Kaskaskia) into three 

 members: The white oolite below (Spergen), the St. Louis Lime- 

 stone (proper), and the Ste. Genevieve Limestone.-^ This proce- 

 dure perhaps led Worthen to include the Spergen and Warsaw in 

 the St. Louis Limestone as he understood it. 



"Illinois Geol. Surv., Vol. I, p. 42, 1866. 



"Illinois. Geol. Surv.. Vol. I, p. 41, 1866. 



^^Missouri Geol. Surv., 1st and 2nd Ann. Repts., p. 60, 1855. 



=iMissouri Geol. Surv., 1855-1871, p. 292, 1873. 



