Class-book of GeologyMacmillan and Company, 1886 - 516 páginas |
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Página 63
... siliceous coverings . Beds of con- cretionary brown ironstone are formed in Sweden from 10 to 200 yards long , 5 to 15 yards broad , and from 8 to 30 inches thick . During winter when the lakes are frozen over , the iron is raked up ...
... siliceous coverings . Beds of con- cretionary brown ironstone are formed in Sweden from 10 to 200 yards long , 5 to 15 yards broad , and from 8 to 30 inches thick . During winter when the lakes are frozen over , the iron is raked up ...
Página 80
... Siliceous Sinter round the vents whence the water is discharged , where it forms a white stone rising into mounds and terraces with fringes and bunches of coral - like growth . Where many springs have risen in the same district , their ...
... Siliceous Sinter round the vents whence the water is discharged , where it forms a white stone rising into mounds and terraces with fringes and bunches of coral - like growth . Where many springs have risen in the same district , their ...
Página 81
... siliceous sinter , and ochre . In these deposits the remains of terrestrial vegetation , also of insects , birds , mammals , and other animals are not infre- quently preserved , and remain as permanent memorials of the life of the time ...
... siliceous sinter , and ochre . In these deposits the remains of terrestrial vegetation , also of insects , birds , mammals , and other animals are not infre- quently preserved , and remain as permanent memorials of the life of the time ...
Página 110
... siliceous diatoms , but containing also other siliceous organisms ( radiolarians ) and calcareous fora- minifera ( Fig . 31 ) . Yet one further illustration of plant - action in the build- ing up of solid rock may be given . Some sea ...
... siliceous diatoms , but containing also other siliceous organisms ( radiolarians ) and calcareous fora- minifera ( Fig . 31 ) . Yet one further illustration of plant - action in the build- ing up of solid rock may be given . Some sea ...
Página 112
... siliceous diatoms , but containing also other siliceous organisms ( radiolarians ) and calcareous fora- minifera ( Fig . 31 ) . Yet one further illustration of plant - action in the build- ing up of solid rock may be given . Some sea ...
... siliceous diatoms , but containing also other siliceous organisms ( radiolarians ) and calcareous fora- minifera ( Fig . 31 ) . Yet one further illustration of plant - action in the build- ing up of solid rock may be given . Some sea ...
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Términos y frases comunes
abundant accumulated acid augite basin beds bones bottom Brachiopods calcareous calcite carbonate of lime Carboniferous chapter characteristic chiefly clay containing corals Cretaceous crinoids crystalline crystals cycads decay deposits detritus Devonian earth earth's crust Eocene Europe evidence example extinct fauna feet thick fishes fissures fossils genera geological history geologist glacier globe gradually granite gravel ground iron Jurassic kinds known lakes land lava layers limestone living lower marine marked marls masses materials Mesozoic miles mineral matter Miocene molten mountains natural North occur Old Red Sandstone organic remains original Paleozoic period Permian plants and animals Pliocene present preserved probably quartz rain records regions rivers salt 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 tion trace Triassic upper valley various vegetation veins vent volcanic