The Solutrean hypothesis argues that people from Europe may have been among the earliest settlers of the Americas.[2][3] Its notable recent proponents include Dennis Stanford of the Smithsonian Institution and Bruce Bradley of the University of Exeter.[4] This hypothesis contrasts with the mainstream archaeological orthodoxy that the North American continent was first populated by people from Asia, either by the Bering land bridge (i.e. Beringia) at least 13,500 years ago,[5] or by maritime travel along the Pacific coast, or by both. The idea of a Clovis-Solutrean link remains controversial and does not enjoy wide acceptance. The hypothesis is challenged by large gaps in time between the Clovis culture and Solutrean eras, a lack of evidence of Solutrean seafaring, lack of specific Solutrean features and tools in Clovis technology, the difficulties of the route, and other issues.[6][7]