[amr] GEOLOGY OF SOME CITIES IN EASTERN CANADA 159 
The Lorraine formation—Immediately overlying the Utica shales 
throughout the district south of Montreal there are seen black or dark 
brown and buff or rusty-weathering shales and arenaceous mudstones of 
tne Lorraine formation. ‘These constitute a thickness of several hun- 
dred feet of strata occupying the country south and east of Montreal, 
whose strike is in a general north-easterly and south-westerly direction 
as far as St. Lambert, and then swerves in a southerly direction toward 
St. Hyacinthe and the international boundary. At Chambly, along 
the Richelieu river, Rivière des Hurons, on Lot 5, Concession LIIL., of 
Chambly Canton, near Rougemont, and Belæil station (Grand ‘Trunk 
Railway), along the valley of the Richelieu river generally, and to the 
eastward the Lorraine formation or highest member of the Ordovician 
system forms the bed rock upon which the newer Pleistocene forma- 
tions have been deposited, which produce such rich soils. 
In several of the localities just mentioned the shales of this forma- 
tion have proved to be highly fossiliferous, and Lamellibranchiata, as 
can be readily expected from the nature of the deposits are predominant 
types. A few corals, a number of graptolites and some univalves and 
cephalopods are also present. Amongst the most characteristic species 
are the following :—/favistella stellata, Zygospira Headi, Pterinea 
demissa, Byssonychia radiata, Clidophorus planulatus, Orthodesma paral- 
lelum, Protowarthia cancellata, Cyrtolites ornatus. 
GENERAL SUMMARY. 
In summing up the strata of the Ordovician system comprising the 
Potsdam, Calciferous, Chazy, Bird’s Eye and Black River, Trenton, 
Utica and Lorraine formations in their normal succession they con- 
stitute probably not less than 1,275 feet in thickness of beds overlying 
the subjacent Archean floor. 
From a number of records of borings for wells obtained and of 
drillings examined by the writer from the Montreal district, various 
estimates have been formed of the probable thickness to be assigned to 
the different geological formations traversed by the drill. In the case 
of the Hochelaga well, stated by the driller, Mr. Bell, to have reached 
a depth of 2,535 feet, there is given an unprecedented thickness to the 
sedimentary series in this district. Mr. Bell informs the writer that 
the drill “ went down into the Potsdam sandstone,” which was reached 
at about 2,500 feet in depth. This would nearly double the thickness of 
the Ordovician strata of the Montreal district as known in their normal 
development and in the case of this Hochelaga well would leave upwards 
of 1,250 feet of strata unaccounted for. A portion of this thickness, 
