348 
STRATIGRAPHICAL GEOLOGY 
and constitutes a taxonomic unit by itself. As such the succession 
should rank as one of the great serial subdivisions. A complete 
recast of Early Carbonic formations of the Continental Interi¬ 
or is foreshaddowed, wherein diastrophic movement is the basic 
principle. 
Systematic grouping of the rock terranes of the Mississippi Val¬ 
ley was a matter of slow growth. It was a gradual evolution of con¬ 
ceptions concerning the relationships of the various formations as 
new facts laboriously accummulated became avialable. Conse¬ 
quently every arrangement provided for was necessarily somewhat 
transitory. Before final adjustment which the backward develop¬ 
ment of information imposed much shifting of units was required. 
Were the entire successions then held in perspective, as is now 
possible, none of the old schemes would be found to be satisfactory. 
The faunal schemes of Williams and of Ulrich are as faulty as 
the strictly lithologic plans of the early workers. Only in propor¬ 
tion as the rock succession reflects regional diastrophism is a 
terranal classification natural and worth while. 
If today one were to view anew the Early Carbonic rock 
succession he would doubtless be inclined to group the strata very 
differently from the arrangement which has gradually developed 
during the last fifty years. Conspicuous among the distinguishing 
features is a three-fold lithologic subdivision. At the base a great 
shale succession inherited directly from Devonic times, is properly 
segregated under the designation Waverleyan Series. To an almost 
unbroken sequence of limestones, which forms the median member, 
the term Mississippian Series seems naturally restricted. Then, 
beginning with Aux Vases sandstone is an extensive sequence of 
sandstones, chiefly, with some shales and limestones, a much re¬ 
peated succession not very unlike the famed Missourian Series of 
Kansas. This seems introductory to the Coal Measures. Its pro¬ 
per designation is probably Kaskaskian Series. 
By this grouping the St. Louis and Ste. Genevieve limestones 
formerly placed with the Kaskaskia formations under the title of 
Tennessean Series go with the next lower series, the Mississippian 
section. Therefore, Tennessean as a serial term loses usefulness 
and is best dropped; and Chester Series, lately revived in this 
sense necessarily gives way to prior name. 
Keyes 
