The period of ridicule seems to be ending in a bevy of new (qnd beautiful) pre Clovis sites tht daate (C14 that is) to 18 to 21K years .
Most of these really old sites are long the East Coast of the US and in Chile. Recent(2016) articles in NATURE and March 2017 EARTH mag, state that Archeology is now clustering round a 4 zone of entry into the Americas by ancient folks, with what looks like an admission that data is favoring a multi-pathed entrey into these continents
1 The earliest (oldest) path is the Atlantic Coastal route with tools similar to modified bifacial point s, similar to Solutrean points. % sites hqve been cataloged with dates of 14.5 to 20K years old. PLUS, several offshore sites hve yielded artifacts that place human hunters and megafauna prey in contact. This supports a Solutrean source .
2The Western "Kelp Hiway" route. another coastl pathway that sttes that the early exporers used water craft to skirt along the ice fields and the sailors relied on resources in the Kelp beds for food. The dtes of these explorations and settlements is about 13K years
3The Southwest Route-However the South American sites were settled (qnd when), travelers from the few sites like Monte Verde Chile seemed to travel N n East to settle in the Gulf Cost of US qnd the Southern Appalachians
4 Last (by time of occurence) was the traditional Beringean migration through an "ice free" zone. The data is now quite good that the "Ice free"conditions didnt occur at 13.5K years as ws preached by the Clovis First people. Then, when the ice free conditions occurred, Core data suggests that it took almost half a millennium to regrow vegetation that attracted animals which were used for food by the early migrations.
So the continents were, by all evidence we see, already populated with widely spread out settlements of Paleo hunter gatherers.
So, it seems that archaeologists, first scornful of anything that suggested the Paleo people were able to build an trvel in boats, are now clustering around a hypothesis that more strongly relies upon boat travel in both the Pacific and Atlantic routes.
Im sure there will be much more because the thought collectively occurred to these researchers that" HEY We may have to get wet"
Ill keep tuning in (actually I was just reading my mags)