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1:250 000 Geological Map
This range of geological maps show the general geology of the area, they come in either folded (for taking on the field), or flat (for wall mounting)
Buy from UKGE |
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1: 50 000 Geological Map
This range of geological maps show the localised geology, they come in either folded (for taking on the field), or flat (for wall mounting)
Buy from UKGE |
Devonian
GEOGRAPHY AND CLIMATE: Gondwanaland still in Southern Hemisphere, Eurasia and North America lie in the tropics, Shale's, Slates and Old Red sandstones laid down as continents flood during warm, dry climate. TERRESTRIAL ANIMAL LIFE: Flightless insects, spiders and the first amphibians. PLANT LIFE: Primitive, large spore-bearing plants from the first forests Horsetails, club mosses appear. SEA LIFE: Horn Corals, Brachiopods, ammonites, Crinoids, conodonts and Trilobites. The age of Fish's, jaws and jawless bony fish, armoured fish, lobe-fin fish and cartilaginous fish all abundant. |
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Geological Guide to Achanarras
(The Devonian Rocks of Achanarras Quarry)
The Caithness Flagstones of the Achanarras Quarry from the Devonian period are of the Achanarras Beds. It is difficult to determine the exact zones since the quarry during the end of its production period started to infill with spoil. The fish beds are laminae, originated as non-glacial varves. The upper fish bed is between two beds of thinly-interlaminated siltstone and shale with mound structures where as the lower fish beds are between thicker laminae of shale and coarse siltstone and shale with shrinkage cracks. The fish bed can be easily seen since the upper fish bed is between two zones of a black bed with mound structures and the lower fish bed sits under a third black band.
(Caithless Flags, Achanarras Quarry)
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