Coal Measures of Kansas. — Keyes. 351 
related localities. It makes little difference, so far as present 
considerations are concerned, whether or not the correlated 
sections were, by Swallow, correctly paralleled. The worth 
of his work as a whole must be judged by the correctness of 
the observations at the typical places. 
In the lower Coal Measures, or Des Moines series. Swal- 
low's Lower Coal series constitutes the major part of what is 
now called the Cherokee shales. Included in the latter, how- 
ever, are his Fort Scott Marble series, which is composed 
chiefly of unimportant shales, and the lower shaly portion of 
his Fort Scott Coal series. The principal limestones of the 
last named "series" and the whole of his Pawnee Limestone 
series forms what has since been termed the Henrietta terrane. 
The thickness of these was very much overestimated by 
Swallow, but not more so than is to be expected under the 
circumstances under which he measured them. 
When we come to the beds called by Swallow the Marais 
des Cygnes Coal series it is questionable whether the term 
could not be regarded as essentially coextensive with the later 
called Pleasanton terrane. The recognized basal limits of 
both are the same. With very slight change the upper limita- 
tion of the Marais des Cygnes could be made to coincide with 
the base of the Bethany, the same as the Pleasanton. The 
great thickness ascribed to the Marais des Cygnes Coal series 
is manifestly largely due to repetition of the section. Swallow 
himself states that "some of the strata may be duplicated in 
this series, as they are very much disturbed where the sections 
were made." He also says of certain localities that it is almost 
impossible to make a correct section. It is not improbable, 
also, that, owing to the lack of good outcrops in this level 
country of eastern Kansas, he mistook, in his correlations, a 
part of the Thayer shales for shales underlying the Bethany 
(his Well Rock series), as he did in the case of what is now 
known as the Lawrence shales. However the chief localities 
given are all east of the line of the Bethany escarpment, in- 
dicating rather clearly that there was actually a duplication of 
beds in this part of his section, as he suspected. jXhe a])pro- 
priateness of the title Marais des Cygnes, from the river of 
that name, is further indicated by the fact that at that time 
the term covered also all that part of the Osage river above the 
