Boellstorff J
Science. 1978 Oct 20;202(4365):305-7. doi: 10.1126/science.202.4365.305.
Confusion due to the conceptual usage of classic North American Pleistocene stage terms indicates the need for a new or revised terminology. The Pliocene-Pleistocene boundary has tentatively been dated about 2.5 +/- 0.1 x 10(6) years. Glacial deposits in the central United States older than about 2.2 x 10(6) years may span that boundary.
由于北美经典更新世阶段术语的概念性使用造成的混淆表明需要一个新的或修订的术语。上新世-更新世边界暂定为约250±10万年。美国中部年龄超过约220万年的冰川沉积物可能跨越了该边界。