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abundant accumulated agencies already America animals become beds called carbonate carried cause characteristic coal coast complete condition connected consists continents coral course covered Cretaceous crust deep deposit depth Devonian direction divided earth erosion eruptions evident example exist fact falls feet fishes fissures folded geological give glaciers greater hundred important interior islands kinds known lakes land lava less limestone living lower mass matter miles mountains mouth natural nearly observed occur ocean organic origin Palćozoic pass period plants portion position present probably produced range reach reef region remains represented rise rivers rocks runs sand sediments seen separated shells showing shown side Silurian similar soil sometimes species springs stone strata stratified streams structure surface Tertiary thick tion true usually volcanic waves whole
Page 243 - ... a supposition could he account for the almost complete blotting out of certain forms of life and the appearance at a later period of wholly new and more highly developed forms, without intermediate stages. "Geological history," he wrote, "like all other history, has its period of comparative quiet, during which the forces of change are gathering strength, and periods of revolution, during which the accumulated forces manifest themselves in conspicuous changes in physical geography and climate,...
Page 102 - J" and cd became the everglades, and its mangrove islands the hammocks which overdot this swamp. In the mean time, ». «., while n" b", the present southern coast, was still a line of keys, another reef was formed further out. This became in time converted also in the line of keys a' b', and will eventually be added in its turn to the mainland, and become the southern coast, — the shoal water between a" b" and a' b' with its mangrove islands becoming another everglade with its hammocks.