Straparolhis from Southeastern loica. — Keyes. 195 
able and that the gradations are so complete that the generic 
limitations heretofore usually assigned are clearly untenable. 
Briefly stated the general characters of Straparollus are : 
Shell rather thick, planorbiform, or depressed conical, broadly 
and often deeply umbilicated ; whorls angular or rounded, 
usually closely coiled, but often barely in contact ; aperture 
sharply pentagonal to sub-circular ; labrum generally sharp. 
The surface of the volutions is for the most part smooth, or 
showing only numerous lines of growth ; but sometimes Avith 
one or more distinct longitudinal carinse. 
Passing now to the species represented in the locality already 
mentioned it is found that they are six in number ; four of 
which are from the Kinderhook beds, and one from each of 
the two divisions of the Burlington limestone. Perhaps the 
most typical form of the series is S. macromphalus Winchell, 
[figs. 4a, 4b, 4c], a shell of medium size, with about four reg- 
ularly rounded volutions and the spire more elevated than in 
any of the other five. It is of considerable interest to note the 
close relationship of this species and certain congeneric forms 
from the Devonian rocks, particularly S. cyclostomus (Hall) 
described from Iowa City, sixty miles to the northward from 
the city of Burlington and just beyond the limits of the Iowa 
Sub-Carboniferous area. This type finds its extreme develop- 
ment in Straparollus {Euom/phahis) springvalensis (White), 
from the Kinderhook beds of Humboldt county, Iowa, in 
which the spire is very much elevated, the umbilical cavity 
exceedingly deep and the volutions numerous. 
Associated with S. macrortipJialus is S. harrlsi Winchell 
[figs. 5a, 5b, 5c]. It is nearly of the same size as the preced- 
ing, but has the spire somewhat more depressed, the umbilicus 
smaller, and the upper portion of the body whorl slightly 
flattened giving rise to an obtuse but noticeable angularity 
near the sutural line. A much smaller species also found at 
this locality is S. ammon (White and Whitfield), which is very 
similar to the Spergen Hill, Indiana, form — S. {Euomphalus) 
spergenensis (Hall). 
In the oolitic band of the Kinderhook the large S. ohtusus 
(Hall) [figs. 2a, 2b, 2c] occurs, but is not common. The shell 
is composed of about six volutions, the upper surfaces of which 
are in the same plane, as shown in fig. 2c. The umbilicus is 
