40 Canadian Record of Science. 
way’s track is built, was perfectly dry. That this was an 
exceptionally dry year, was shown by the enormous num- 
bers of dead shells of Limnea, Planorbis, Physa and other 
genera, which, everywhere, rendered the ground crisp 
under the tread of the foot. The ground was covered by a 
heavy growth of grasses of three or four species, scattered . 
everywhere in great patches, each grass occupying its own 
patches to the exclusion of the other grasses. The soil is a 
heavy black loam, and the surrounding circumstances all 
clearly show how such soils have been formed in the val- 
leys of the Lower Assiniboine and of the Red River, and 
around Lake Manitoba, by the annual decay of such marsh 
grasses. 
To the westward of the Big Grass Marsh and the West- 
bourne Marsh, circumstances are changed. The country, 
after leaving the gravel ridges which strike the line of the 
Manitoba and Northwestern Railway at Arden, becomes of 
a slightly rolling character, and increasingly so some dis- 
tance farther westward. As Neepawa is approached, the 
surface loam is underlaid by sand. Boulders become exposed 
in the river valley at Minnedosa and in the side valleys 
leading into it—washed out, no doubt, from the drift clays 
which at a greater or less depth underlie the surface soil. 
At Birtle, the Laurentian boulders are not only common 
in tbe deep valleys, especially on the eastern side, of the 
Bird Tail and of Snake Creek,—appearing in almost a 
solid mass of both large and small boulders at one point at 
the creek level near Birtle—but are also on the surface of 
the prairie above. They are in the latter case, generally 
more common in and upon the surface of the low ridges 
which here and there somewhat parallel each other. 
Proceeding still westward, boulders are not frequent in the 
valley of the Assiniboine River at Fort Ellice and at the 
railway crossing eighteen miles up the stream, but the bed of 
the river at the ford is formed entirely of very large sized 
gravel. Nor do boulders appear again until the country 
beyond Langenburg is reached. Here there are two or 
three gravelly knolls rising twenty-five or thirty feet above 
the general level, like the Spy Hills, also gravelly knolls, 
