Dec., 1912.] Ordovician Section, Lake Huron Area. 
45 
In Ohio, Whiteavesia pholadiformis and Modiolopsis concentrica 
come in at the base of the Fort Ancient division of the Waynesville 
bed, and continue to the top of the Waynesville, but they are 
represented by at least very similar forms even in the Liberty. 
Under these circumstances it was natural at first to regard these 
strata, on Manitoulin, which carry the Whiteavesia pholadiformis 
and Modiolopsis concentrica fauna as Richmond. However, the 
brvozoans submitted to Dr. Ulrich tell a very different story, and, 
until further evidence has been accumulated, it is regarded wiser 
to remove them from the Richmond column. For collecting 
purposes these beds are well exposed for a distance of about two 
miles along the shore between Wekwemikongsing and the Rich¬ 
mond Clay Cliffs on the eastern side of Cape Smyth. The total 
thickness of the Wekwemikongsing section on [Manitoulin island 
may equal 100 feet in the Cape Smyth area. 
8. Richmond Strata on Manitoulin Island. 
C. Waynesville Beds, or Lower Richmond. 
Overlying the Wekwemikongsing beds, with their Lorraine fauna, 
is a series of interbedded limestones and clay shales of undoubted 
Richmond age. At the base of these undoubted Richmond beds, 
Hebertella insculpta , frequently associated with Catazyga headi, 
is almost invariably present, and since Hebertella insculpta and 
Catazyga headi, on Manitoulin, are limited to the basal part 
of these beds, both fossils here serve as valuable diagnostic 
fossils. Associated with these fossils in the same layers occur: 
Streptelasrna rusticum, Columnaria alveolata, Protarea papillata, 
Rhombotrypa quadrata, Hebertella occidentalis , Platystrophia darks - 
villensis, Strophomena huronensis, Rafinesquina alternata very flat 
form, Pledambonites sericea, Rhynchotrema perlamellosa, Zygospira 
modesta, Cyclonema bilix, and Pterinea demissa. These associated 
fossils, however, are not confined to the Hebertella insculpta and 
Catazyga headi horizon but range upward for variable distances 
into the overlying Richmond. 
The lower pact of the Richmond, on Manitoulin, is by far the 
richest in fossil remains, and many species, especially among the 
brachiopoda, appear to be confined to this lower part. Between 
Gore Bay, Kagawong, and Little Current, a conspicuous coral 
reef, from one to three feet thick, containing Columnaria alveolata 
and Calapoecia huronensis, frequently is found between 35 and 45 
feet above the base of the Hebertella insculpta horizon. It has 
been found that while most of the fossils which begin their range 
at or near the Hebertella insculpta horizon reach the Columnaria 
reef horizon, many of these species do not extend their range 
beyond this reef. Among the latter may be mentioned: Protarea 
papillata, Constellaria polystomella, Rhombotrypa quadrata, Crania 
scabiosa, Rafinesquina very flat form, Pledambonites sericea, 
