Complex sentence: It is noted as a location of controversial artifacts believed by some archaeologists to indicate human habitation of the New World earlier than the Clovis culture, who were previously believed to be the first people in North America.
Split into simpler sentences: It is noted as a location of artifacts which some archaeologists believe to indicate human habitation of the New World earlier than the Clovis culture. The latter were previously believed to be the first people in North America.