306 JOURNEY TO THE SHORES 
given a name to one of the portages. The rocks 
which form the bed of the river, and the nume- 
rous islands, belong to the granite formation. The 
distance made to-day was thirteen miles. 
July 21.—We embarked at four A.M. and 
pursued our course down the river. The rocks 
cease at the last portage ; and below it the banks 
are composed of alluvial soil, which is held to- 
gether by the roots of trees and shrubs that crown 
their summits. The river is about a mile wide, 
and the current is greatly diminished. At eight 
we landed at the mouth of the Salt River, and 
pitched our tents, intending to remain here this 
and the next day for the purpose of fishing. 
After breakfast, which made another inroad on 
our preserved meats, we proceeded up the river 
in a light canoe, to visit the salt springs, leaving 
a party behind to attend the nets. This river is - 
about one hundred yards wide at its mouth. Its 
waters did not become brackish until we had as- 
cended it seven or eight miles; but when we had 
passed several rivulets of fresh water which flowed 
in, the main stream became very salt, at the same 
time contracting to the width of fifteen or twenty 
yards. At a distance of twenty-two miles, in- 
cluding the windings of the river, the plains com- 
mence. Having pitched the tent at this spot, 
we set out to visit the principal springs, and 
