THE CROWSNEST VOLCANICS. 
13 
exposed at the surface, and of the exposed part, only occasional 
localities were visited. However, it has been stated that the 
greatest thickness of the beds is in the vicinity of the Crows- 
nest mountain, and also that it is probable that the thickness there 
is about the maximum, so that the main centre of eruption 
may safely be considered to have been in that vicinity. There 
is no evidence to show that there was more than one vent, unless 
the elongate form of the deposit may be considered as such. 
However, this may be due to current action in distributing 
the sediments and further and more detailed study might throw 
light on this subject. 
It is the writer’s opinion that there was a linear arrange- 
ment of several vents in a north and south direction about the 
meridian of Coleman, Alberta . 1 
Conclusions. 
At the time when the deposition of the Crowsnest volcanics 
began, the area they now cover was occupied by a shallow sea 
probably of fresh water, containing low marshy islands. There 
is no recognized evidence to show whether the vents emptied 
into the air, or were submarine; any cones that may have been 
built up above sea-level would naturally be destroyed during 
the incursion of the sea in Benton time. The thickness of the 
deposits in relation to their lateral extent seems to indicate that 
the beds are due to the simultaneous effect of several small 
volcanoes of moderate activity, rather than to the action of 
one large vent. The eruptions were of the explosive type, un- 
accompanied by flows except very locally, and took place in 
continual sequence during a relatively short period of time. 
By far the greater part of the ejected material fell into the sea, 
and there was deposited in more or less well stratified beds. 
^his statement was written in April 1913, and in September of the same 
year, Dr. C. H. Clapp informed the writer that he had found a probable 
volcanic neck at Coleman. It is not improbable that still others may be 
discovered. 
