Preliminary Notes on Cincinnatian and Lexington Fossils 305 
25 to 28 millimeters in width. No depression was noticed on the 
basal surface. Four hexagonal plates occur in a width of 7 milli- 
meters. The depressions left by the plates are concave as in 
Pasceolus darwini. The association of Pasceolus intermedins 
with a Silurian rather than Ordovician fauna suggests that when 
this species is better known it will prove distinct from Pasceolus 
darwini. 
Streptelasma vagans, nom. nov. 
{Plate XI, Figs, i, A, B, C.) 
The species of Streptelasma from the Richmond group of Ohio, 
Indiana, and Kentucky, long known as Streptelasma corniculum., 
has been referred more recently to Streptelasma rusticum, from 
the Hudson River group of Snake Island, in Lake St. John, in 
the province of Quebec, in Canada. Recently, L. M. Lambe 
has figured a specimen of Streptelasma rusticum, and, judging 
from his figures, this species is much more nearly cylindrical 
toward the top, and relatively more narrow than is true of the 
species characteristic of the Richmond of the region affected by 
the Cincinnati geanticline. Streptelasma canadensis, Billings, 
from the Hudson River group on Drummond Island,* in Lake 
Huron, appears to have the inner edges of the septa more nearly 
vertical, producing a wider calyx, with a flatter bottom. 
In the specimens from the Whitewater beds, at Dayton, Ohio, 
the corals more nearly resemble Streptelasma canadensis in form, 
but are less wide at the top. The number of primary septa is 
about 60 to 65. The secondary septa, approximately equal in 
number, do not extend more than one millimeter from the thick- 
ened walls of the corals; frequently they appear not much more 
conspicuous than prominent striations. The calyx is conspicu- 
ously narrower at the base than near the top. In a specimen 25 
millimeters wide at the top, the twisted central area at the base of 
the calyx equals about 8 millimeters in width, and the width of 
the base of the calyx, limited by the inner edges of the septa, does 
not exceed 10 millimeters. The free edges of the septa are not 
denticulated. While this species undoubtedly is closely related 
to Streptelasma canadensis, it is not regarded as identical. 
Geological position. The type specimens are from the White- 
water bed at Dayton, Ohio. At this horizon they are abundant 
