Eric Hultén, beginning in the 1920's, spent decades
studying the flora of Kamchatka, northeastern Siberia, Alaska, and the Yukon Territory. He noticed that plants had "ranges symmetrical to a line through Bering Straight", and that both regions were unglaciated (Hopkins, 1998). Hultén realised that the growth of the Pleistocene ice caps must have lowered the sea-level enough to expose a land bridge at the current Bering sea location. He named this intercontinental land bridge Beringia. Later, J.S. Creager and D.A. McManus (1965) discovered Pleistocene drainage patterns on the Chukchi Sea floor proving that a land bridge had indeed existed. The idea of Beringia was well established by the late 1960's, and drove a ton of research that persists today in an effort to reconstruct the paleoenvironments on or around the land bridge, specifically at the end of the last Ice Age. More recently, a 1,000 km² fragment of intact land bridge was found preserved beneath volcanic tephra from the North Seward Peninsula which provided information about the seasonal paleoclimate (Groetcheus et al, 1994). New or refined research methods and technology have led to recent revisions of the paleoenvironments of Beringia.