CORRELATION OF MISSISSIPPIAN MEMBERS. 77 



the Burlington section. The " Chouteau " is number 9 of the 

 Louisiana locality. The "Lower Burlington limestone" em- 

 braces numbers 7 and 8 of the Burlington section; the "Upper 

 Burlington limestone" numbers 9 and 10 of the same. The two 

 together form numbers 10 to 14 inclusi^^e, at Louisiana. The 

 "Keokuk limestone" is numbers 1 and 2 of the Keokuk expos- 

 ures, number 1 of the Warsaw section, and probably number 1 

 of the Sainte Genevieve outcrops. The " geode bed" appears 

 as number 3 at Keokuk and number 2 at Warsaw; the typical 

 " Warsaw " embraces numbers 4 to 6 of the Keokuk section 

 and numbers 3 to 5 at Warsaw. The 'Saint Louis limestone" 

 is represented by number 7 at Keokuk, number 6 at Warsaw, 

 all of the Saint Louis section, and number 3 at Sainte Gene- 

 vieve, while number 2 of the same section has been called the 

 Warsaw limestone (not typical). The Sainte Genevieve lime- 

 stone of Shumard is number 4 of the Sainte Genevieve-Sainte 

 Mary outcrops. The "Aux Vases sandstone" forms bed num- 

 ber 5 between Sainte Genevieve and Sainte Mary, and under- 

 lies number 1 of the Chester section a few miles north of the 

 town. The "Kaskaskia limestone" includes numbers 1 to 4 of 

 the Chester section, and the " Chester shales " numbers 5 to 7 

 of the same section. The Coal Measures are represented at 

 Keokuk by number 8, at Sainte Genevieve by number 7, and 

 at Chester by number 8. 



The great abundance of fossils in all the members of the 

 Mississippian series of the interior basin makes the faunal 

 test perhaps the most important of all, in attempting a rational 

 classification of the rocks of the region. Heretofore the re- 

 mains of ancient life found in these rocks have been considered 

 either from a purely biological point of view, or, as in the 

 majority of cases, from the stand-point of the mere species- 

 maker; and it is only within the past few years that large num- 

 bers of species taken together have been compared with one 

 another, in order to marshal the confused hosts into orderly 

 arrangements, so that faunas may be studied as a whole. 



The second important consideration to be taken into ac- 

 count in the present connection is the stratigraphical testimony. 



