Eastern Kansas and Nebraska. 169 
this conclusion, it should be remembered, is not based upon 
structure alone, or other lithological characters, but also upon a 
careful and thoroughly scientific investigation and comparison of 
e fossil plants characterizing each bed or subordinate stratum, 
But it is not alone upon the evidence of structure, and their 
fossil flora, that the Illinois Coal-measures are known to be 
to the same horizon as the regular Coal-measures of Indiana, 
Kentucky, Ohio, Pennsylvania, &c., for we bave also the unmis- 
takable evidence of its group of animal remains. It is true, as 
in all other formations, species sometimes occur in these rocks in 
one State that do not in another, but a miscellaneous collection 
of shells, Corals, Crinoids, Bryozoa, &c., from the Coal-measures 
of any part of Illinois, would be at once referred to that horizon 
y any person familiar with the forms characterizing rocks of 
the same age in any of the States above mentioned. Long lists 
of species might be cited to illustrate this point, but it is wholly 
unnecessary; we may remark, however, that Pleurotomaria 
spherulata, P. tabulata, Euomphalus catilloides, and Macrocheilus 
primigenius, of Conrad, which are among the most eharacteris- 
ic fossils of the Coal-measures, not only in Illinois, but in Jowa, 
Missouri, and in part in Kansas, were first descri y Mr. 
Conrad from the regwar Coal-measures of Western Pennsylvania. 
Tn relation to the Coal-measures of Illinois belonging to the 
attention to the subject know this to be the ease, and even Mr. 
and Iowa, from which it is onl y separated by the broad valley of 
denudation scooped out by the Mississippi river. Following the 
Missouri and Iowa Coal-field westward, we find that it passes 
&naterruptedly into Kansas and the southeast corner of Nebraska 
—the valley of the Missouri, owing to the northwestward incli- 
‘Ration of the strata, not going deep enough to cut it into two 
distinct fields, 
: hroughout all this area, these rocks are characterized by essen- 
y the same fauna. As in all other formations, some spectes 
re local in their geographical range, but the majority are not, 
aid, as elsewhere stated, most of them range into the Coal-meas- 
we. of Kentucky, Indiana, Ohio, and some even into Pennsyl- 
Vania, while comparatively very few of them have even been 
oo of being identical with forms occurring 1n any lower 
Position, 
Bi) oes 
_ Teeks, is derived from the presence or absence of certain types 
i of Brachiopoda, it is but fate that we should not dismiss this part 
