364 
GLACIAL BORDER OF SPOKANE 
plain between the Huckleberry Mountain and Mount Spokane, 
moving in a direction west of south. On reaching the valley of 
the Spokane River it probably encountered a substantial obstruc¬ 
tion in the form of a mountain of granite which is at present repre¬ 
sented by Little Baldy lying between Hillyard and Pleasant Prairie. 
Such an hypothesis would satisfactorily explain why the ice did 
not cross the valley farther east, and is to some extent supported 
by the abundance of morainic materials from this source, and 
present appearances of the hill. 
By crossing the Spokane Valley a dam was formed and waters 
of the upper Columbia drainage basin were apparently impounded 
forming Lake Spokane. While the ice seems to have extended 
onto Pleasant Prairie to the east of Little Baldy, no evidence is 
yet found of glaciation on the south side of Spokane Valley east 
of Spokane city. Abundant scattered boulders of granite are to 
be found throughout the valley up to 2500 feet elevation. In fact, 
in a paper read before the Geological Society of America in 1910 
Hershey set forth as evidence of the existence of a Glacial lake in 
the valley occupied by Coeur d’Alene Lake and Coeur d’Alene 
River, the presence of granite and basalt boulders on the terraces 
of the last mentioned stream at Kellogg, Idaho, which could not 
have been derived from the mountains of that region, but could 
only have been carried in on floating ice. The elevations at 
which Mr. Hershey found these boulders corresponds fairly well 
with the distribution of similar boulders where the writer has 
been able to make observations from Spokane to head of Liberty 
Lake. Most conclusive evidence in the way of ice-rafted boulders 
is to be found in the angular granites entirely detached from all 
Glacial till, or river-wash, on the top of the basaltic mesa two miles 
southeast of Vera, in Spokane Valley (Sections 19 and 30, T. 25 
N., R. 45 E.) -These boulders lie at an elevation of 2300 to 2400 
feet. Another evidence of the presence of a lake is to be found 
in the appearance of the sand deposits which have the appearance 
of having been laid down in water, in the north wall of the valley 
between Trent and the Hutton settlement, and a still further evi¬ 
dence in the Mica Outlet. This outlet may be readily studied on 
the topographical map of the Spokane Quadrangle. It lies between 
Mica Peak and Moran Mountain, at the village of Mica, twelve 
