112 Henry Gannett — MotJier Maps of the United States. 



upon which it is worthy of being rej^resentedjand thus to make 

 an estimate of the area of the country which can be mapped from 

 existing material upon each of several different scales. 



The scales which I shall consider are 1, 2, 4, 8 and 16 miles to 

 an inch. I exclude from consideration, for the present, the ter- 

 ritory of Alaska. 



On a scale of 1 mile to an inch, I find that only 100,000 square 

 miles can be mapped, or about one-thirtieth of the area of the 

 country (that area being a trifle over 3,000,000 square miles). 

 This area possible to map includes the states of Massachusetts, 

 Rhode Island, Connecticut and New Jersey and parts of numer- 

 ous other states, mainly in the north. It includes a narrow strij) 

 of topography along. the sea and lake coasts and the Mississippi 

 and Missouri rivers. Two-thirds of this area is the work of the 

 United States Geological survey, the balance being mainly that 

 of the United States Coast and Geodetic survey. 



On tlie scale of two miles to one inch, an area of 360,000 

 square miles has been surveyed by the Geological survey. No 

 work adapted to representation upon that scale has ever been 

 surveyed by other organizations. This area is widely scattered 

 over the country. On this scale, therefore, an area of 460,000 

 square miles, or between one-fifth and one-sixth of the area of 

 the country, can be mapped. 



On a scale of 4 miles to one inch, the work of several organiza- 

 tions is included, .viz, the exploration of the 40th parallel, the 

 Hayden, Powell and Northern Transcontinental surveys, the 

 Black hills survey, the 4-mile work of the AVheeler survey, and 

 the 4-mile work of the United States Geological survey. The 

 work of these organizations foots up, after deducting the over- 

 lapping areas, 460,000 square miles. All this area is in the Cor- 

 dilleran region. 



The area in the United States which can be mapped on a 

 scale of 4 miles to one inch is, tlierefore, 920,000 square miles, or 

 between one-third and one-fourtli of the area of the country. 



The original maps of this area are all of such character as to 

 furnish material for representing all the three elements of a 

 topographic map — the hydrography, the culture and the relief. 

 They include most of those parts of the country which present 

 high relief, including the southern Appalachians and most of the 

 Cordilleran region. With the exception of 60,000 square miles 

 furnished by the Wheeler survey, the relief of this area can be 

 expressed quantitatively by contours. 



