Class-book of GeologyMacmillan, 1896 - 404 páginas |
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Página 4
... vegetation . Below the peat there might occur a layer of soft white marl full of lake - shells , such as may be observed on the bottoms of many lakes at the present time ( compare Fig . 30 ) . These three layers — oyster- bed , peat ...
... vegetation . Below the peat there might occur a layer of soft white marl full of lake - shells , such as may be observed on the bottoms of many lakes at the present time ( compare Fig . 30 ) . These three layers — oyster- bed , peat ...
Página 7
... vegetation and of animal life belonging to types that have long since passed away . It must be evident , however , that were we to confine our inquiries merely to its surface , we should necessarily gain a most imperfect view of the ...
... vegetation and of animal life belonging to types that have long since passed away . It must be evident , however , that were we to confine our inquiries merely to its surface , we should necessarily gain a most imperfect view of the ...
Página 14
... vegetation , the decay is no doubt retarded ; but in the absence of vegetation , the outer crust of the decayed layer is apt to be washed off by rain , or when dried to powder may be blown away and scattered by wind . As fast as it is ...
... vegetation , the decay is no doubt retarded ; but in the absence of vegetation , the outer crust of the decayed layer is apt to be washed off by rain , or when dried to powder may be blown away and scattered by wind . As fast as it is ...
Página 15
... vegetation of the surface . Traced from below upwards , the rock is found to become more and more broken and crumbling , with an increasing number of rootlets that strike freely through it in all directions , until it passes insensibly ...
... vegetation of the surface . Traced from below upwards , the rock is found to become more and more broken and crumbling , with an increasing number of rootlets that strike freely through it in all directions , until it passes insensibly ...
Página 16
... Vegetation sends its roots and rootlets through the rotted rock . As the plants die , they are succeeded by others , and the rotted remains of their successive generations gradually darken the uppermost decom- posed layer . Worms ...
... Vegetation sends its roots and rootlets through the rotted rock . As the plants die , they are succeeded by others , and the rotted remains of their successive generations gradually darken the uppermost decom- posed layer . Worms ...
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Términos y frases comunes
abundant abundantly accumulated acid Ammonites basin beds bones bottom Brachiopods calcareous calcite Cambrian carbonate of lime Carboniferous Chapter characteristic chiefly clay containing corals Cretaceous crinoids crystalline crystals decay deposits detritus Devonian earth earth's crust Eocene eruptive rocks Europe evidence example extinct fauna feet thick fishes fissures formations fossils genera geological history geologist glacier globe gneiss gradually granite gravel ground iron Jurassic kinds known lakes land lava layers limestone living lower marine marls mass materials Mesozoic miles Miocene molten mountains natural North occur Old Red Sandstone organic remains original Palæozoic period Permian plants and animals Pliocene present preserved probably quartz rain regions represented rivers sand schists sea-floor sediment sedimentary rocks shales sheets shells siliceous Silurian slopes soil solid sometimes species stone strata stratified stream structure substance surface terrestrial Tertiary trace Triassic Trilobites upper valley various vegetation vent volcanic