Complex sentence: This would indicate the presence of humans well before the last glacial period, nevertheless considerable doubt over the validity of these findings has been raised by many other researchers, and the pre-Clovis Topper dates remain controversial.
Split into simpler sentences: This would indicate the presence of humans well before the last glacial period. Nevertheless, considerable doubt over the validity of these findings has been raised by many other researchers, and the pre-Clovis Topper dates remain controversial.