Evidence has been found in the northwest USA that an early stone implement technology, known as 'Western Stemmed' projectile points, were manufactured at least 11,070 to 11,340 radiocarbon years ago, making them concurrent with or possibly earlier than the Clovis culture (dated to 13,000 calendar years ago) in North America. The early occupants of the Paisley caves in Oregon had ancestral Siberia-East Asian origins, and were using the caves at least as far back as 12,450 radiocarbon years ago.
     The broad, concave-based, fluted Clovis projectile points often associated with early Americans who lived about 12,000 to 13,000 years ago were not found in the caves.
     The dating of the Western Stemmed projectile points to possibly pre-Clovis times adds to the debate about different technologies overlapping in time and whether or not they developed separately. The results suggest that the Clovis culture may have developed or originated in the southeastern United States and moved westward, while the Western Stemmed tradition originated in the west and moved eastward.
     Clovis technology has only been found in the New World, whereas Western Stemmed technology is similar to stone technology seen in northeastern Asia. At least three other Western USA sites also contain only Western Stemmed points in deposits of this early period.

Edited from EurekAlert!, Popular Archaeology (12 July 2012)