Marcou.] 
202 
[Jan. 21, 
The Secretary then read by title the following paper : 
GEOLOGY OF THE ENVIRONS OF QUEBEC, WITH 
MAP AND SECTIONS. 
BY JULES MARCOU. 
Between the vegetable mould and the subjacent rock, there is, 
all round Quebec, a deposit of glacial mud with scratched pebbles 
and boulders ; and also above that glacial formation, sand deposits 
containing marine shells actually living in the Gulf of St. Law- 
rence. Near the top of Montmorency falls, 250 feet above the 
St. Lawrence river, that boulder formation and sand with- marine 
shells, is well developed, and can be found even higher up, five 
miles northeast of Indian Lorette. I shall not refer to those 
superficial formations of the Quaternary period or surface geology 
but limit my remarks and observations to the stratigraphy of the 
older rocks. 
Montmorency. — In following the river Montmorency from the 
u Natural Steps” down to the bridge, the brink and the foot of 
the Montmorency fall, we have the following strata : At the 
Natural Steps, the Trenton limestone is well developed, with all its 
characteristics, as well lithologically, as paleontologically, abso- 
lutely like the typical Trenton limestone near Chazy village, and 
at Trenton falls in New York. In the dark blue, almost black, 
limestone, stratified in beds varying from six inches to one foot 
in thickness, the Trenton fossils are very numerous, more especi- 
ally : Calymene Blumenbachii , Ceraurus pleurexanthemus , Illaenus 
Milleri , Trinucleus concentricus , Asaphus platycephalus, Conularia 
Trentonensis , Orthoceras , Murchisonia , Bellerophon , Orthis , Stra- 
phomena , Leptaena , Prasopora , etc. 
Coming down the river, near the road west of the bridge, and 
at the bridge, the limestone is not so thick as it is at the Natural 
Steps ; and the first thirty feet lying on the quartzites and the 
conglomerates, is composed of thin beds, varying from half an 
inch to three and four inches thick only, which give to the cliffs 
of limestone about the bridge the appearance of a dark brown 
brick wall. The limestone strata in contact with the quartzites 
lies on the protuberances and inequalities of the quartzites, which 
