NOTE.—These maps, projected without reference to political divisions, are designated by some prominent feature found on them. They are of uniform size on a scale of 1.62500 or about 1 mile to 1 linear inch on the map. They are issued as working editions for the use of geologists of the United States Geological Survey, and are not published for distribution or sale. About 900 sheets have been produced since 1883. covering, more or less, nearly every State and Territory. Massachusetts, Rhode Island. New Jersey, and the District of Columbia are completely mapped. Some of the earlier maps are on a scale of 1:125000 and 1:250000.