To ages of weathering; the bulk of it is composed of finely comminuted particles of sand, clay and other minerals, among which are imbedded larger or smaller stones of more refractory nature.
Sand is by itself of little value except for striking cuttings, for which purpose fine clean sharp silver sand is the best; and a somewhat coarser kind, if it is gritty, is to be preferred to the comminuted sands which contain a large proportion of earthy matter.
The work has been going on for ages, and the finely comminuted particles of rocks form the main bulk of the soil which covers much of the earth's surface, the rest of the soil being composed chiefly of the remains of roots and other parts of plants.
The comminuted seed is placed inside a vessel connected with an upright refrigerator on trays or baskets, and is surrounded there by the volatile solvent.
The method consists essentially in cutting up the fatty matter into small fragments, which are transferred into vessels containing water, wherein the comminuted mass is heated by steam, either under ordinary pressure in open vessels or under higher pressure in digestors.
The discharge of the comminuted material takes place through an aperture, which is covered by a thin steel plate perforated with numerous slits about Ath in.
The comminuted mass, forming a more or less coarse meal, is either expressed in this state or subjected to a preliminary heating, according to the quality of the product to be manufactured.
The till is presumably made in part of preglacial soils, but it is more largely composed of rock waste mechanically comminuted by the crccpiiig ice sheets; although the crystalline rocks from Canada and some of the more resistant stratified rocks south of the Great Lakes occur as boulders and stones, a great part of the till has been crushed and ground to a clayey texture.
Are composed chiefly of comminuted shells drifted and deposited by the wind, and they are very irregularly stratified, as is usually the case with wind-blown deposits.