194 
IOWA ACADEMY OF SCIENCES. 
Plate xx. 
Figure 1. 
Melonites multipora. 
la. 
Ambulacrum (enlarged). 
lb. 
Apical disk (enlarged). 
Ic. 
Interambulacral plate (enlarged). 
Figure 2. 
Oligoporus danse. 
2a. 
Ambulacral plates (enlarged). 
2b. 
Interambulacral plates (enlarged). 
Figure 3. 
Archaeocidaris wortheni. 
3a. 
Ambulacral plates (enlarged). 
3b. 
Interambulacral plates (enlarged). 
GEOLOGICAL SECTION OF THE Y. M. C. A. ARTESIAN 
WELL AT CEDAR RAPIDS, IOWA. 
BY WILLIAM HARMON NORTON. 
The record of this well is of special importance because it 
supplements and corrects the published records of the earlier 
city wells. It is based almost wholly upon drillings taken at 
frequent intervals directly from the sand pump. Unfortunately 
samples of the first ninety feet were not saved, within which 
space the drill must have passed through the beds lying 
between the lowest recognized Devonian and the Le Claire beds 
of the Upper Silurian. The interval, in part at least, can be 
supplied from outcrops in the immediate vicinity. The geolog- 
ical section at Cedar Rapids is as follows: 
FEET. 
Fayette breccia including the Gyroceras beds of Calvin 11 
Independence shales (Kenwood beds) 30 
Otis limestone (Sinrifer subumhonus beds), 30 
Within a block of the well there outcrops, three feet above 
low water in the Cedar river, a locally persistent layer of the 
Otis; a brown, non-magnesian limestone macrocrystalline heav- 
ily and irregularly bedded and with large calcite nests. This 
is underlain at wateiTevel by a buff thin-bedded limestone. The 
brown limestone makes a locally persistent horizon not over 
twelve feet from the base of the Otis, where at numerous 
exposures along the Cedar below town, noticeably at Otis, it 
passes into a heavily-bedded, soft, buff magnesian limestone. 
Between the outcrop of this buff limstone, which we may 
