26 
locality indicate that T. dalii has the fossula upon the side of least curvature, 
possesses no secondary septa, has fewer primary septa, and usually bears 
Bhort thecal spines. T. centralis (Edwards and Haime) from the Chester of 
Illinois, 1 has fewer septa, a fossula enlarging inwards and situated upon 
the side of least curvature. T. t multilamella (Hall), from the Mississippian 
of Utah, is a larger form with a much more rapid increase in diameter. 
Specimens from section 2-16 are apparently in a younger stage of 
development than those from the other and higher localities, for, though 
they have 60 to 80 primary septa, they do not take on the short secondary 
septa until a diameter of 25 mm. has been attained; those from the higher 
localities, however, have these secondary septa completely developed at a 
diameter of 15 mm., and faint incipient ones were noted at a diameter of 
only 7 mm. From section 2-14 one specimen shows a few secondaries at a 
diameter of 23 mm., another at 15 mm. Since these corals of 2-16 reach a 
maximum diameter of only 35 mm., the majority lack the secondary septa 
and in none was a septa length greater than 3 mm. noted. The specimen 
from section 2a-14, identified provisionally as T. dalii } may possibly be a 
greatly retarded T. minnewankensis. 
Locality and Horizon . In the Minnewanka region in the Pennsylvanian 
of sections 2-9 (?), 16 (C); 3-7 (R); 3a-3 (C). 
Genus, Lithostrotion Lhwyd 
Liihostrotion whitneyi Meek 
1877. Lithostrotion whitneyi Meek, U.S. Geol. Expl. 49th Par., vol. 4, p. 
58, PI. 6, figs. 1-lc; White, 1877, U.S. Geol. Surv. W. 100th Mer. f 
vol. 4, 103, PI. 6, figs. la-c. 
Remarks. This species was originally described from the Mississippian 
limestone of the Wasatch range, Utah. Later White 2 noted it from Fossil 
hill, White Pine county, Nevada; from this locality he also listed Hemipron - 
iies crenutria , Spirifer cameratus, and Seminula argentea. Meek, in addition, 
cited from the same locality 3 Productus semireticulatus, P . prattenianus , 
and P . longispinus. L. whitneyi is thus associated in Nevada with a Penn- 
sylvanian fauna. The corallites from Nevada differ from Meek's type 
description and figures only in their somewhat greater diameter (8 mm. 
to 14 mm.) and in the presence of three to five rows of vesicles in the outer 
zone; this latter character is associated with the larger size, for in the 
Albertan form it is the large individuals which have more than two or 
three rows of vesicles. Meek's type has usually from one to three rows of 
vesicles. The Minnewanka specimens are thus somewhat transitional 
between these two types, though distinctly nearer Meek's than White’s 
form. L. mamillare sublaevis Meek is also a multivesiculate form of the L. 
whitneyi type, but with a very broad columella. It was found in the lime- 
stones of the Sierra Nevada mountains at Bass’ ranch in Shasta county, 
California, associated with such Pennsylvanian species as Fusulina cylin - 
drica , Productus semireticulatus , and Reticularia perplexa. 
1 Loc.cit.,p. 72. 
*Loc.cit. 
1 Loo.cit. 
