92 Geological Results of the Earth’s Contraction. 
d. Distribution of the heat attending submarine action, causing meta- 
morphic changes. 
V. Earthquakes, or a vibration of the earth’s crust, consequent 
on a rupture, internal or external, and causing vibrations of the 
sea besides other effects, (iii, 181.) 
VI. Epochs in geological history, (ii, 187.) 
VII. Courses of mountains and coast lines, and general form of 
continents, determined to a great extent by the general direction 
of the earth’s cleavage structure, and the position of the large 
areas of greatest contraction. 
Continents (or areas of comparatively slight contraction) often 
therefore present ranges of mountains near their borders, and 
these mountains are highest and abound most in volcanoes around 
the largest ocean, (the Pacific, iii, 398.) Thus the existence of 
such continental areas determined the existence of the mountains 
nature of the earth’s crust. They have had their laws of growth, 
involving consequent features, as much as organic structures. In 
this remark, we refer not, under the term continent, to the sur- 
faces of land bounded by the water line; for these, by slight sub- 
sidences, are greatly varied in form and size :—but to those ex- 
tended areas, which, were there no water, would stand raised far 
above the intermediate oceanic depressions. 
eanie action and | ;. pe of heat, goi 
the fractures attending the gradual folding and uplifting of strata while beneath 
the sea. Similar views, of earlier date, are offered by De la Beche, in his very 
able Report on Cornwall, Devon and W. Somerset, 8vo, 1839, The de-bitaminr 
zation of the anthracite coal of the Appalachians appears to be attributed Dy 
rof. Rogers essentially to this cause. (Trans. Assoc. Amer. Geol. and Nat-, 
1840-1842, p. 473.) 
