8 
AUG. F. FOEESTE 
group of columnals, of which six columnals occupy a length of 
about 2.3 mm. This second group also has a deep, wide depres- 
sion at the top, as though the inner part of the body-cavity of 
the tegmen were connected directly with the lumen. The upper 
margin of this second group is overlapped by the descending 
extensions of the protuberances on the basal plates of the theca. 
If the proximal columnals are the youngest, then the second 
group may be due merely to a rejuvenation of the process which 
gave rise to the first group. When the upper margin of the first 
group had attained such a size that it crowded upon the over- 
lapping extensions of the basal thecal plates, a new series of 
smaller columnal plates appears to have been started. It is 
conceivable that stereom was added to the exterior of the col- 
umnals after the more central parts already had been formed. 
In the figured specimens, the surface of the thecal plates ap- 
pears to be smooth; however, on many of the loose thecal plates, 
evidently belonging to the same genus, the surface of the plates is 
covered by a reticulated series of lines, similar to that shown 
by Brockocystis tecumsethi (Billings) (plate III, fig. 1) from the 
top of the Manitoulin dolomite, on Manitoulin island, in Ontario, 
Canada. It is possible that there are two species of Brocko- 
cystis in the Brassfield strata of Ohio, but if that be true, this 
fact has not yet been definitely determined. 
Locality and position. The specimens here figured were ob- 
tained in the lower part of the Brassfield formation, beneath a 
trestle along the railroad about two miles west of Peebles, Ohio. 
They were in the upper part of the cherty layers which occur a 
short distance above the base of the Brassfield formation in the 
southern part of the state. The following section is exposed 
beneath the trestle, in descending order: 
feet. 
Limestone, cherty nodules few 3 
Limestone, in more massive beds, cherty nodules large and numerous . 3 
Limestone, thinner bedded, cherty nodules small and few 2 
Limestone, thin-bedded, no chert noticed 2.5 
Creek level beneath tressle. 
The following fossils were secured here, chiefly from the upper 
half of strata here listed, which belong to the more cherty part 
