Complex sentence: Three archaeologists from Minnesota institutions then conducted a preliminary dig of nine test-holes at and around the site, on July 25, finding no evidence of Norse presence, but a few Native American artifacts, including two quartz flakes, probably waste from arrowhead production.
Split into simpler sentences: Three archaeologists from Minnesota institutions conducted a preliminary dig of nine test-holes at and around the site, on July 25, finding no evidence of Norse presence. They found a few Native American artifacts, including two quartz flakes, probably waste from arrowhead production.