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Bering Land Bridge
DEFINITION: The present-day floor of the Chukchi and Bering Seas, which emerged as dry land during Late Pleistocene glacial advances. It is the only route for faunal exchange between Eurasia and North America as it united Siberia and Alaska. It seems to have been breached only in the past 2.5 million years, with the earliest immigrants crossing it about 40,000-15,000 years ago. They were part of a migratory wave that later reached as far south as South America (about 10,000 years ago). During the Ice Age the sea level fell by several hundred feet, making the strait into a land bridge between Asia and North America, over which a considerable migration of plants and animals, as well as man, occurred. That period also allowed the transit of cold water currents from the Pacific into the Atlantic.
DEFINITION: A Roman fort site in northeast England, on the River Tyne, dating to 79-80 AD. It burned and was rebuilt in c105, but was neglected when Hadrian's Wall with its own forts was built not far to the north. When the Roman frontier was pushed further north in 139, the fort was reconstructed in stone and later, when the frontier fell back to Hadrian's Wall once again, Corbridge flourished as a market town and a military supply depot. Remains of military quarters, granaries, and temples may still be seen.
CATEGORY: structure
DEFINITION: A structure forming a road over a river, etc. or allowing passage between two points above the ground. A bridge can be a simple plank or single arch or an elaborate architectural structure supported by arches, chains, girders, piers, etc. They are made of many different materials. The first bridges were natural, such as arches of rock. The first manmade bridges were flat stones or tree trunks laid across a stream to make a girder bridge. Three types of bridge - beam or girder, arch, and suspension - have been known and built from the earliest times.
brow ridge
CATEGORY: typology
DEFINITION: The part of the skull above the eye orbits, very pronounced in early hominins who had less cranial capacity and an absent or sloping forehead; brow ridges are largely absent in Homo sapiens sapiens.
CATEGORY: artifact
DEFINITION: The case containing the charge for a firearm.
dorsal ridge
CATEGORY: artifact
DEFINITION: The sharp ridge that marks the boundary between flake scars on the dorsal surface of a lithic flake.
median ridge
CATEGORY: artifact
DEFINITION: A ridge that usually runs from the tip of a blade to the hafting area which was formed by collateral flaking techniques in the manufacture of the artifact. The median ridge can be the thickest part of the blade
CATEGORY: artifact
DEFINITION: A raised, angular band, line, or strip about the neck of a vessel
ridge and furrow
CATEGORY: feature
DEFINITION: A pattern of parallel ridges resulting from the plowing of strip fields in medieval and later open field systems. The fossilized remains of ancient plowmarks are a common sight in England, having the appearance of long, rounded parallel ridges with alternating ditches. There is no absolute dating for the ridge and furrow field; a few contentious examples could be Roman in date, while others are as late as the 17th and 18th centuries.
ridge tile
CATEGORY: artifact
DEFINITION: Stone or ceramic tile used along the ridgeline of a roof, usually shaped to sit over the ridge itself to provide a water-tight seal with the roof sections on either side.
CATEGORY: feature
DEFINITION: An ancient communications route following the line of an upland ridge. these are tracks along the watersheds from hillfort to hillfort, used by prehistoric man. Often there is no artificially constructed roadway, but some routes became Roman roads or medieval droveways. The dates of the finds extend back beyond the Middle Ages. Important British ridgeways are the Jurassic Way along the limestone ridge from Dorset to Lincolnshire, the Icknield Way in the Chilterns, and the Pilgrims' Way along the North Downs.
scar ridge
CATEGORY: artifact
DEFINITION: Any boundary of an individual stone flake scar.
spout and bridge pot
SYNONYMS OR RELATED TERMS: spout-and-bridge vessel
CATEGORY: artifact
DEFINITION: A distinctive closed vessel with two spouts connected by a strap handle, popular in southern coastal Peruvian cultures with antecedents in the Initial Period ceramics of the Hacha complex. Typically it is a closed kettle-shaped vessel, but its defining characteristic is a pair of vertical tubular spouts joined to each other by a strip or bridge. Sometimes, however, one spout terminates as a whistle or as a modeled life figure. It was particularly popular with the Nasca and Chimu but has been found in many other New World contexts (e.g. Paracas).
CATEGORY: artifact
DEFINITION: Transverse ridges added to the faces of a flat ax mounted in a right-angled cleft haft to transfer some of the impact from the base of the cleft to the tips. Axes with stop-ridges form an intermediate step in development between the flanged ax and the palstave. The term also refers to a ridge on a celt or pipe which prevents one part from slipping too far over another.

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