The same thought occurred to me when I was looking at the zones, and noticing that it didn't appear to cover all of TDC's territory. Another thought that occurs to me, however, is to wonder how accurate the maps are. And do they only represent the surface? It's quite possible for a mafic intrusion to underlie other rock. If subsurface drilling has never taken place in an area, or if the person who made the map never had access to the results of the drillhole, then we wouldn't see a mafic intrusion, even if it was only 10 feet underground but entirely covered.
Ultimately, the maps don't mean anything to me because there's so much surrounding them that I do not know.
MR
