Aug. 9, 2002, 10:45AM BONING UP ON HISTORY Skeletal remains may be 11,000 years old By TERRY KLIEWER Copyright 2002 Houston Chronicle LAKE JACKSON -- The gummy clay of coastal Texas holds plenty of secrets, but it may have given up one of its oldest when routine excavation near here uncovered prehistoric human bones. alt="remains" vspace="2"> John Everett / Chronicle Archaeologist Robert d'Aigle unearthed bones three years ago in the San Bernard River National Wildlife Refuge in south Brazoria County. He may have found only the third human skeleton in North America that dates back at least 10,000 years. The...