Some Canadian Rocks containing Scapolite. 191 
ago, sent to Mr. Hoffmann of this Survey for examination, 
there was, however, one small specimen which exactly 
resembled the Oedegarden rock, and which, when sliced 
and examined with the microscope, proved to be identical 
with it. Unfortunately, we were unable to obtain any 
further specimens or to ascertain the locality from which it 
came more precisely than that, as above mentioned, it was 
from near the town of Arnprior. The large collection of 
rocks in the museum of the Geological Survey of Canada 
was then carefully examined, and sections were prepared 
of all those which at, all resembled this rock in appearance. 
An examination of these sections resulted in the discovery 
of three other specimens, from widely separated localities, 
rich in scapolite, but unlike the Arnprior rock, containing 
also a considerable proportion of plagioclase. 
The first of these specimens was collected by the late Mr. 
‘Vennor at Mazinaw Lake, in the township of Abinger, in 
the county of Addington; the second was obtained by Mr. 
Coste at the Robertsville or Mississippi Iron Mine, on lot 3, 
range VIII. of the township of Palmerstone, in the county 
of Frontenac, and the third was collected by Dr. Bell from 
lot 28, range I. of McDougall, in the Parry Sound district. 
All three rocks are of Laurentian age, and come from that 
great stretch of Laurentian country lying north of Lake 
Ontario and south of of Lake Nipissing and the River 
Ottawa. The eastern half of this area was examined by 
Mr. Vennor, and found by him to be rich in amphibolites, 
dioritic schists and diorites; a very common, coarse-grained 
variety of the latter being called by him ‘“ blotched diorite,” 
and it is associated with these dioritic rocks, whose occur- 
rence at Mazinaw Lake is mentioned by Mr. Vennor, that 
the Arnprior and Mazinaw Lake rocks apparently occur, 
The rock from the Robertsville Mine is found associated 
with crystalline limestone and granite. In some places it 
forms the wall rock of the magnetite, between 50,000 and 
60,000 tons of which have been mined. The mode of occur- 
rence of the McDougall rock is described by Dr, Bell in the 
