20 
AUG. F. FOERSTE 
constant for about one-third of a volution, and diminishes to 
three columnals in 1.5 mm. at the end of the last third of a 
volution. 
Throughout by far the greater part of the length of the column 
the latter has been split in two along a plane parallel to the plane 
of curvature. This exposes a darkened line, never more than 
three-tenths of a millimeter in width, which evidently locates 
the lumen. The latter is distinctly nearer the convex side of 
the curvature of the column, and, in transverse sections of the 
stem, is seen to be wider in a direction at right angles to the 
plane of curvature. Under a lens it appears possible to detect 
four additional planes, indicated by slightly darker coloring, 
suggesting original pentamerism (plate II, fig. 3) with the un- 
paired segment on the convex side of curvature of the column. 
Why this unpaired segment should split so smoothly along its 
middle is unknown, but the immediately opposite suture evi- 
dently is the one along which the stem should split most readily. 
There is no conclusive evidence of the presence of two rows 
of cirri, nor of points of attachment for the latter, although 
vague traces of short cirri appear to be present at one point. 
Locality and position. Holotype found up stream from Silver 
Springs, on the head waters of Caesars Creek, 4f miles south- 
east of Xenia, Ohio. The locality is over a mile and a half up 
stream from the Xenia-Wilmington pike. Here it occurs in 
the upper half of the Brassfield limestone, associated with the 
following fauna: Cyathophyllum facetus, Haly sites catenularia, 
Hemitrypa ulrichi, Chasmatopora angulata, Clathropora frondosa 
clintonensis, Phaenopora expansa, Ptilodictya expansa, Ptilo- 
dictya americana, Pachydictya hifurcata, Pachydictya ohesa, 
Rhinopora verrucosa^ Rhipidomella hyhrida, Platystrophia day- 
tonensis, Leptaena rhomhoidalis, Brachyprion moderately convex, 
Strophonella daytonensis, Strophonella hanoverensis, Atrypa mar- 
ginalis, Cyclonema daytonense, Illaenus ambiguus, Illaenus day- 
tonensis, Proetus determinatus, and Encrinurus thresheri. 
Remarks. The reversal of curvature at the broken end of this 
column is indicated by the distinctly greater length of the last 
three columnals along the inner side of the coil. This suggests 
