Standard sized postcard. Promotional giveaway for the State Survey. A view of bedrock geology - what is under the surface dirt and gravel. Lots of metamorphic (changed by heat and pressure) rocks in MA! Even the blue and green areas are metamorphic rocks. The bright reds are granite or granite-like rocks. Cape Cod and the islands are in purple. That means they are made of unconsolidated glacial sediments. Given 20 000+ years, they will probably wash away.
I am away for about 8 days so this will be it until I come back. Enjoy.