Making contour maps of the top of bedrock is difficult with limited amounts of data. Making contour maps of the top of bedrock is difficult with limited amounts of data. By superadministrator|2019-03-19T18:24:56-05:00March 19th, 2019| Share This Story, Choose Your Platform! FacebookTwitterLinkedInRedditTumblrPinterestVkEmail About the Author: superadministrator