This map, based on a map from the Maine GIS Library, shows major towns and islands in Penobscot Bay. Yellow on the west side of the bay shows the approximate location of lime deposits. Pinkish tan shows granite quarrying areas, both along the southern part of the bay and also in Frankfort. Reddish-brown depicts the location of some of Penobscot Bay's brick industry. More brickmaking occurred upriver in Orrington and Brewer, on the east side of Penobscot Bay.