Cerionites Dactylioides Owen. — Calvin. 53 
this point two hundred and fifty feet. At the gas well east 
of the city the drill struck a boulder at one hundred and fifty 
feet and at the well drilled southeast of the city one hundred 
and fort} T feet of drift were penetrated. 
At the extreme western edge of the basis a terminal moraine 
ie Been; large boulders of foreign rock were originally scat- 
tered over the fields, but have been piled up for fences and a 
great number have been hauled away. 
At the most northern point of the basin, Sugar creek hav- 
ing channeled its way through the surrounding rock, enters 
and follows the north and western rocky wall and upon leav- 
ing the basin has cut its deep channel through the solid rock 
for many mile-. 
The only glacial markings on the bed rock are seen at the 
most western edge having the direction of 10 degrees E. of N. 
The origin of these basins in the glacial region of Indiana 
is evidently due to the erosive power of water before the 
Pleistocene period. 
I. It is known by the study of living glaciers that glacier- 
abrade but do not erode hard rocks, and both modern and 
extinct glaciers are known to have flowed, over even loose 
moraines and gravels.* 
II. So deep a basin with such a small area could not have 
been eroded by ice leaving the faces of the enclosing walls 
vertical. 
III. The stria' observed on the bed rock at the western 
edge of the basin are not parallel with the walls at this point. 
IV. There are basins, similar to these of the state of Indi- 
ana, to be seen in the Sub-carboniferous rocks of the south 
be}*ond the limit of the glacier-. 
ON THE STRUCTURE AND PROBABLE AFFINITIES 
OF CERIONITES DACTYLIOIDES OWEN. 
By S. Calvin, Iowa City. 
In his Report of a Geological Exploration of <> />"/•/ of Towa, 
Wisconsin and Illinois, made under instructions from the 
Secretary of the Treasury of the Onited State- in the autumn 
of the year 1839, Dr. David Dale Owen describes and figures 
*Dr. J. W. Spencer, Proceedings American Association for the Ad- 
vancement of Science. Vol. XXXVII, pasje 198. 
