By analyzing and dating the contents of each layer in the deep-sea core, scientists have reconstructed what happened one day 65 million years ago.Such cores are typically conical or pyramidal in shape; to produce regular even blades a certain degree of preparation is needed as well as periodic rejuvenation.technique using a hollow metal tube driven into the ground to lift a column of earth for stratigraphic study.This technique is used in underground or undersea exploration.A core sample is a roughly cylindrical piece of subsurface material removed by a special drill and brought to the surface for examination.知识概况：russiasingle4russiasingle4russiasingle4russiasoc... The core is undisturbed and the sediment contacts, soil boundaries, and structures are intact and can be described accurately.
SYNONYMS OR RELATED TERMS: core tablet CATEGORY: artifact DEFINITION: A roughly round slightly wedge-shaped flake of flint with the remains of flake beds around the outside edge.
Such flakes are the product of extending the life of a core that has become uneven or difficult to work but which still has the potential to yield further blades.
Both these activities produce their own distinctive debitage..
These include possessions of the great patrician families of Rome, such as paintings illustrating Dionysiac mysteries, jewels, and magnificent gold and silver household furnishings.
The cubiculum of one villa at Boscoreale is preserved in the Metropolitan Museum of New York City and other items are kept at the Louvre.