Coal Measures of Central Iowa — Kei/es. 403 
feet, and are exposed at a number of places in the bluffs of tbe 
yicinity. The limestone bands are from eight to twelve inches 
thick and in places fossilifero us. On Capitol Hill at an exposure 
on the corner of Court avenue and east Ninth street these cal- 
careous layers are separated by only four feet of clay; while a 
quarter of a mile south-east of this locality, on the Wabash 
railway, the lower band is overlaid by a marly seam, an inch and 
one-half in thickness, which affords Productus muricaius N. & 
P. and a number of other species in greatest profusion. 
These bands have yielded the following fossils: 
Rhombopora lepidodendroides Meek. muricatus N & P. 
Cyathophyllum ti.rquium Owen. cora d'Orb. 
Lophopliyllum proiifenim McO. Athyris subtilita Hall. 
Eupachycrinns pragii. M & W. Retzia mormonl Mareou. 
Synocladia bisprialis S wallow. Spirifera ra'-.iata Sow. 
Chonetes verneuiliana N & P. camerat<t Morton. 
mesoloba N & P Spiriferina kentucken.si.s Shumard. 
Productus semirecticulatus Martin. Streptorhynchus crenistrius Pbiliips. 
The present separation of the lower and middle coal meas- 
ures does not appear, at least in the vicinity of Des Moines, to 
be sustained by either the stratigraphical or lithological char- 
acters; nor is the palasontological evidence in harmony with 
such a division. It is indeed to be doubted whether in Iowa 
the coal measures are really separable into more tha two well 
marked sections. The evidence in substantiation for such a 
division need not be considered here, though it may be stated 
that it is at an horizon considerably higher than the variegated 
shales just alluded to, that the fauna of the strata designated 
as middle coal measures begins to assume an upper coal meas- 
ures facies; and that it is even higher before the lithological 
characters approach those of the upper division. 
Apropos to the casual reference to the ceuological features 
of this portion of the state, mention may be made to the recent 
discovery in the drift at Des Moines of a mass of rather soft 
ferruginous sandstone, charged with fossils of unmistakable 
Cretaceous type, the greater part of which are in a good state 
of preservation. When first discovered the mass was perhaps 
two feet in diameter and contained upwards of a dozen species 
of fossils. A few of the best preserved specimens were taken 
at the time, and the place revisited a few days later for the pur- 
pose of securing the whole piece, but unfortunately Avorkmen 
bad broken and removed it. The species obtained were: Otodus 
appendiculatus Ag., Lamna Texana Roemer, Fasciolaria cul- 
