- I'm going to e-mail The Oregon Historical Soceity a link and a contact for an engineering group called Geotechnology here in STL that does GPR or Ground Penetrating Radar. My mom did PR work for them once. ~Chris **************************************************************************** Our WebPage! Http://WWW.GeoStL.com Mail List Info. //www.freelists.org/cgi-bin/list?list_id=geocaching Mail List FAQ's: //www.freelists.org/help/questions.html **************************************************************************** To unsubscribe from this list: send an email to geocaching-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field