148 
Continuing up-stream, the section is now interrupted 
by a few rods of sandy and grass-covered beach, and 
then we come upon the little cliff where igneous beds are 
intercalated in the limestones, just at the contact of the 
Black River and Trenton. The thin-bedded layers in 
the upper part of the cliff contain Platystrophia lynx, 
Parastrophia hemiplicata and other Trenton fossils. There 
are four beds of the igneous rock, separated by thin layers 
of limestone. The igneous beds are of the same material 
as the dykes at Mile End, and are probably contempo- 
raneous with them. The thickest is 32 inches (81 cm.) 
thick and quite coarse grained, but it does not seem to 
have affected the limestone above and below it more than 
a quarter of an inch from the contact. 
POINTE CLAIRE AND STE. ANNE-DE-BELLEVUE. 
Black River, Lowville, Aylmer Limestone (Chazy), 
Beauharnois and Potsdam.—In the two large quarries south 
of Pointe Claire the upper 25 feet (7-6 m.) of strata are 
Black River, with, however, comparatively few fossils. 
Columnaria halli, Maclurites logani, and a few cephalopods 
are present. The lower 7 feet (2-1 m.) are Lowville, 
exceedingly rich in fossils, of which Tetradium cellulosum 
and Tetradium fibratum make up whole layers. There is 
also a variety of pelecypods, gastropods and cephalopods. 
This is the typical locality for Lophospira daphne, which is 
quite common here. Bathyurus extans, Isotelus gigas, 
Orthoceras multicameratum, and Orthoceras recticameratum, 
are other common forms. There is no great lithological 
difference between the Lowville and the Black River, and 
the contact can only be found by observing the range of 
Tetradium cellulosum. 
The outcrop of the Aylmer limestone (Chazy), which 
is on a small point extending into Lake St. Louis, is small 
and a rather unsatisfactory one. The common fossils found 
here are Hebertella vulgaris and Hebertella costalis, occur- 
ring in a grey, coarse-grained limestone on the right-hand 
side of the point. It will be noted that the Black River 
strata at the quarries dip toward the river, so that there 
is either a syncline or a fault between the quarries and this 
exposure of Aylmer limestone (Chazy). 
A hundred feet (30-4 m.) west of the station of Ste. 
Anne-de-Bellevue is a small, water-filled, abandoned 
