69 
ence with the Assineboine. The water-courses to the south 
of the Big Chyenne, chief among which is the James River, 
all point to the south, and are so far as observed in their 
upper courses, marked by valleys of considerable width,— 
sometimes of several miles—but forming only shallow de- 
pressions in the face of the plateau. None of those observed 
contained running water, but are generally characterized by 
“chains” of lakes of variable size, from that of small ponds, 
to those many miles in length. Almost all of these are very 
shallow. Not only the valleys mentioned, but also the entire 
face of the country is covered with these shallow lakes, ponds 
and puddles, many of which are, however, dry or undergoing 
a process of gradual drying out. This can be seen from the 
fact that some of the dry lakes are full of decaying fresh- 
water molluscs of species still living in wet lakes near by, 
while others show only bleached shells, and still others not 
even these. Many of the lakes are very round, the central 
portion of the dry lakes is generally covered with fine white 
sand with a few isolated Salsolas or Salicornias. Around this 
sand-bed is a circle of larger stones, and around these con- 
centriccircles of different species of plants. The water of all 
the lakes is charged with salts, probably mostly sulphates. 
Mini-Wakan, to judge from its taste and strong action on 
the kidneys, seems to contain Nitrates, some of the ponds are 
also charged with Sulphuretted Hydrogen, and a small lake 
between Mini-Wakan and Mouse River showed strong reac- 
tions of a solution of Alkaline Sulphurets. The waters of 
the Mouse River and of the Big Chyenne, are fresh and 
limpid. 
The entire surface of the eastern plateau is covered by the 
Drift, apparently of northern source, characterized by the 
predominence of boulders of a white, very hard and solid 
siliceous rock, of perfectly homogeneous texture, which be- 
comes enameled by exposure to the atmosphere. At the 
Mini-Wakan one piece of Drift Rock, containing fossils 
(Strophonema?) was noticed. In the southern portion of 
the plateau, below Port Rice, Hills of the Green Sandstone 
formation, mentioned above, are frequent, and the Dog 
