Fossils from the Loiver Coal Measures — Keyes. 23 
ready two or even three times several of his views always 
expressed as the result of "the accuracy of his original observa- 
tions" during the very short space of three years. 
{To be continued?) 
ON SOME FOSSILS FROM THE LOWER COAL MEASURES 
AT DES MOINES, IOWA. 
BY CHARLE9 R. KEYES. 
The fauna of tlie lower Coal Measures as recently discovered 
in the vicinity of Des Moines has proved to be of considerable 
interest; of interest on account of ( i ) the profusion of minute 
molluscan forms, (3) the occurrence of species not hitherto re- 
ported from the state, and (3) the close similarity in many re- 
spects of this and the fauna of the lower Coal Measures of east- 
ern Illinois, particularly that of the superimposing black shales 
of the "Danville" coal, or coal "No. 7" of the general Illinois 
section. Stratigraphically the relations of these two fossilifer- 
ous shales to the principal coal beds are the same — each form- 
ing the roof of the most extensive coal stratum in their respective 
localities; lithologically, the two shales are apparently identical. 
Hitherto, with a very few exceptions only fragmentary fossil 
remains have been obtained from the Carboniferous strata of the 
region around Des Moines; and for the most part the collec- 
tions from this locality have consequently been very meager. 
The discovery then of a fauna embracing, as hereafter enumer- 
ated, thirty-six genera and nearly sixty species, the majority of 
them in a most perfect state of preservation, is, in its bearing 
upon certain phases of Carboniferous life, of especial significance. 
Though economically of far greater importance than any other 
formation in the state, the lower Coal Measures have received 
comparatively little geologic attention; and the two attempts at 
an exhaustive and detailed survey of this formation in Iowa, 
and a correlation of the different Coal horizons were, unfortu- 
nately, rendered abortive by circumstances entirely beyond the 
control of those engaged in the study of the Des Moines valley 
region. In Iowa the lower Coal Measures probably have a max- 
