Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 3 - By Alexander Von Humboldt And Aime Bonpland.
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1. Strata Commonly Called Primitive; Granite, Gneiss And Mica-Slate
(Or Gneiss Oscillating Between Granite And Mica-Slate); Very Little
Primitive Clay-Slate; Weisstein With Serpentine; Granite With
Disseminated Amphibole; Amphibolic Slate; Veins And Small Layers Of
Greenstone.
2. Transition strata, composed of fragmentary rocks (grauwacke),
calcareous slate and greenstone, earliest remains of organized
existence:
Bamboos, madrepores, producta, trilobites, orthoceratites,
evamphalites). Complex and parallel formations; (a) Alternate beds of
grey and stratified limestone, anthracitic mica-slate, anhydrous
gypsum and grauwacke; (b) clay-slate, black limestone, grauwacke with
greenstone, syenite, transition-granite and porphyries with a base of
compact felspar; (c) Euphotides, sometimes pure and covered with
jasper, sometimes mixed with amphibole, hyperstein and grey limestone;
(d) Pyroxenic porphyries with amygdaloides and zirconian syenites.
3. Secondary strata, presenting a much smaller number of
monocotyledonous plants; (a) Co-ordinate and almost contemporary
formations with red sandstone (rothe todtes liegende), quartz-porphyry
and fern-coal. These strata are less connected by alternation than by
opposition. The porphyries issue (like the trachytes of the Andes) in
domes from the bosom of intermediary rocks. Porphyritic breccias which
envelope the quartzose porphyries. (b) Zechstein or Alpine limestone
with marly, bituminous slate, fetid limestone and variegated gypsum
(Productus aculeatus). (c) Variegated sandstone (bunter sandstein)
with frequent beds of limestone; false oolites; the upper beds are of
variegated marl, often muriatiferous (red marl, salzthon) with
hydrated gypsum and fetid limestone. The gem-salt oscillates from
zechstein to muschelkalk. (d) Limestone of Gottingen or muschelkalk
alternating towards the top with white sandstone or brittle sandstein.
(Ammonitis nodosus, encrinites, Mytilus socialis): clayey marl is
found at the two extremities of muschelkalk. (e) White sandstone,
brittle sandstein, alternating with lias, or limestone with graphites;
a quantity of dicotyledonous mixed with monocotyledonous plants. (f)
Jura limestone of complex formation; a quantity of sandy intercalated
marl. We most frequently observe, counting from below upwards; lias
(marly limestone with gryphites), oolites, limestone with polypi,
slaty limestone with fish, crustacea, and globules of oxide of iron
(Amonites planulatus, Gryphaea arcuata). (g) Secondary sandstone with
lignites; iron sand; Wealden clay; greensand or green sandstone; (h)
Chlorite; tufted and white chalk; (planerkalk, limestone of Verona.)
4. Tertiary strata, showing a much smaller number of dicotyledonous
plants. (a) Clay and tertiary sandstone with lignites; plastic clay;
mollasse and nagelfluhe, sometimes alternating where chalk is wanting,
with the last beds of Jura limestone; amber. (b) Limestone of Paris or
coarse limestone, limestone with circles, limestone of Bolca,
limestone of London, sandy limestone of Bognor; lignites. (c)
Silicious limestone and gypsum with fossil bones alternating with
marl. (d) Sandstone of Fontainebleau. (e) Lacustrine soil with porous
millstone grit. (e) Alluvial deposits.)
1. CO-ORDINATE FORMATIONS OF GRANITE, GNEISS AND MICA-SLATE.
There are countries (in France, the vicinity of Lyons; in Germany,
Freiberg, Naundorf) where the formations of granite and gneiss are
extremely distinct; there are others, on the contrary, where the
geologic limits between those formations are slightly marked, and
where granite, gneiss and mica-slate appear to alternate by layers or
pass often from one to the other.
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