i899-'oo ^Transactions '^35 



time, although the wells may be of the same depth, and penetrate 

 identical strata of sand, gravel, etc. . ■-. 



It must not, however, be supposed that stratification of so 

 simple a type as I have described, is at all common. Soil,- by 

 which I mean everything that is not rock, has result^ 

 essentially from the operation of chemical and mechanical forces 

 upon solid rock. The chief of these forces have been, (i) the 

 freezing of water in the pores of the rock, thus breaking it. up ; 

 (2) the action of rain ; (3) the alternate expansion and con- 

 traction by heat and cold ; (4) attrition of stone upon stone at 

 the bottom of rivers and lakes ; (5) the movement of large ice 

 masses (glaciers) ; (6) solution of certain rock components, 

 with the consequent falling apart of the residue ; (7) action of 

 the roots of plants, which action is both mechanical and 

 chemical ; (8) chemical action by oxidation, formation of 

 carbonates, etc. Many of these changes have taken place under 

 water, and every part of the earth's surface has again and again 

 been the bottom of lake or sea, so that soil formed by the means 

 described, does not necessarily remain on the spot which produced 

 it, but may lie hundreds of miles away. Thus, soils which have 

 resulted from the attrition of rock masses in the regions round 

 about Algoma, now cover the fields of Southern and Eastern 

 Ontario. This sort of thing has happened the world over ,^i.,and 

 the carriers of these immense masses of clay, sand, gravel and 

 boulders, have been ocean and river currents ; but above-iall 

 glaciers and icebergs. 



An iceberg is not a large block of clean, pure ice, but a 

 section of a glacier, broken off by the lifting power of the 'ocean 

 when the moving mass has been so far thrust into its waters 

 that their buoyancy overcame the strength of the ice, and'a 

 huge mass snapped off, rose to the surface, and was carried out 

 to sea. This ice mountain contains, frozen into it, perhaps 

 thousands of tons of rock detritus. It floats out to sea, and 

 wherever it melts, this soil-forming material is deposited, per- 

 haps forming a heap or hill, perhaps being strewed along the 

 course of the floating bergs. After a period of submergence, 

 which may be hundreds of thousands of years in duration, sub- 

 terranean forces cause, what was so long sea bottom, to become 

 dry laud ; and we can imagine the condition of things described 



