Now you have. Those (Cactus Hill, Topper and another) are indeed old sites and are possibly in the 20k year old range and they do have Solutrean technolgy but, there are no human remains. The oldest dated skeleton ever found in the Americas is named Luzia, an African looking woman who died at age 24, 11,500 years ago in Brazil. (There has recently been a skeleton, Kennewick Man like, found off the coast of California, on an island, that is expected to surpass the 11,500 year old Luzia skeleton)
If we therefore find them in the USA, one might make the assumption they remained of the same race despite the ocean voyage, BUT I DID NOT SAY THAT.
Furthermore, I said that the oldest humans in NORTH America were at the three sites...I never mentioned South America in any way, so Luzia is of no relevance here.
Many sites in South America are MUCH older than 20,000 years, some do approach 40,000 years. As you say, those people might be African like Luzia, or who knows what. I was discussing North America.