Dec., 1912.] Ordovician Section, Lake Huron Area. 
47 
which occurs eastward at greater intervals. It is the interval 
between these two reefs which usually presents such a meager 
fauna. Locally, however, for instance between Manitouaning 
and Cape Smyth, the lower parts of this section appear richly 
fossiliferous. 
Immediately above the Stromatocerium reef, at Ivagawong and 
Gore Bay, a rich pelecypod, gasteropod, and ostracod fauna, but 
not consisting of many species, comes in. Among these, Ortonella 
hainesi suggests the Whitewater age of the strata involved, while 
Leperditia ccecigena and Primitia lativia are common at certain 
horizons in the Saluda of Indiana but range to the top of the 
Elkhorn in Ohio. Cyrtodonta ponderosa, Ctenodonta iphigenia , a 
large Archinacella , and various species of Lophospira occur. Among 
the species which continue their range upward from below are 
Strephochetus richmondensis, Tetradium huronensis, Hebertella 
occidentalis, Zygospira modesta, Byssonychia radiata, and Pterinea 
demissa. They are all forms capable of continuing existence in 
muddy waters, judging from the frequency with which they are 
found in argillaceous limestones, fine grained sandstones, and 
clays. The total thickness of this upper part of the Richmond, 
from the Stromatocerium reef to the base of the Clinton, varies 
apparently from 45 to 60 feet, on Manitoulin. 
E. Queenstown Shales. 
The northwestern extension of the red clay shales, to which 
the term Queenstown has been applied in the Niagara Falls area, 
is well exposed on the Saugeen peninsula which separates Georgian 
Bay from the main body of Lake Huron. In the vicinity of Colling- 
wood, Meaford, Owen Sound, and westward, these red shales 
evidently represent the strata above the Columnaria reef horizon 
as exposed on Manitoulin. The only fossiliferous strata found in 
these Queenstown shales, however, belong to those horizons above 
the Stromatocerium reef in which ostracods are abundant. In 
addition to Leperditia ccecigena and Primitia lativia , Eurychilina 
striatomarginata and Drepanella canadensis are present, accom¬ 
panied by the Richmond form of Bythocypris cylindrica, Byssony¬ 
chia radiata , Pterinea demissa, a Zygospira resembling Z. ken- 
tuckiensis, Bythopora delicatula, and other characteristic Ordo¬ 
vician fossils. 
At the Forks of the Credit, 65 miles southeast of Meaford, no 
trace of this Richmond fauna was found anywhere in the Queens¬ 
town red clay shale section. 
In the vicinity of Meaford, the highest layers of the Richmond 
fauna occur fully 100 feet above the top of the richly fossiliferous 
Waynesville fauna at the base. The total thickness of the Queens¬ 
town shales, in the vicinity of the Niagara Falls, however, is 
estimated at 1000 feet, so that it may be only the basal part of the 
Queenstown shale which is of Richmond age, although there appears 
no lithological reason for imagining a different age for the upper 
part of the Queenstown section. 
