What was Alfred O Coffins' contribution to biology?

Alfred O. Coffin went to school and received a Master's and Ph.D in Biology at IL Wesleyan University in 1889, he also taught for 2 years at Alcorn Agricultural & Mechanical College. But his greatest accomplishment was The Prigin of the Mound Builders, which tracked the ancient Indian mound builders of the Mississippi Valley to their origin in Southeast Mexico.