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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 |
Jurassic
GEOGRAPHY AND CLIMATE: Gondwanaland continues to break up, Graywacke,
shale and siliceous sediments formed. Continued mountain building.
mild, moist climates over most of the land.
TERRESTRIAL ANIMAL LIFE: Reptiles dominant with Crocodiles, turtles,
lizards and dinosaurs. Pterosaurs and Archaeopteryx take to the air.
Mammals begin to diversify. More advanced insects such as flies.
PLANT LIFE: Cycads, ginkos, conifers, ferns and tree ferns.
SEA LIFE: All major invertebrate groups well represented, ammonites and bivalves successful. Marine reptiles, Ichthyosaurs are Plesiosaurs. |
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Geological Guide to Portland Bill
At the top of the cliffs at Portland Bill, is the Purbeck Beds of Cretaceous age, these are the Lulworth Formation.
Below this is the Jurassic, Portland Beds, Cherty Series. Rocks from the Basal Shell Bed can also be seen in blocks fallen from the cliff.
West of the lighthouse, a raised beach can be examined with local mesozoic rocks, as well as granite, bunter and quartzite pebbles. This is known as the 'Portland Raised Beach', and continues for 100m to a cliff top. Fossils can also be found here as many of the rocks and pebbles are of the Portland Stone and Purbeck Beds.
Portland Raised Beach
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