110 Bulletin 1, Biological Society of Washington, 1918. 



INDEX TO THE U. S. GEOLOGICAL SUBVEY'S 

 1917 MAP OF WASHINGTON AND VICINITY. 



INTRODUCTION. 



The desirability of preparing an indexed map of the region 

 usually considered as appertaining to the Washington fauna 

 and flora has long been appreciated by the writer. Lack of 

 a suitable base, however, has prevented action upon the plan 

 until the excellent new map 77 of Washington and vicinity 

 was published. Although this map does not include the full 

 area, taken in by the varying radii of from 10 to 25 miles 

 used by the different workers, the opportunity seemed the 

 best likely to come within a reasonable period, a fact recog- 

 nized by the Council of the Biological Society which cheer- 

 fully gave the necessary cooperation of financial guarantees. 



The plan has been to index not only all localities named 

 on the base map, but to show by means of the index symbols 

 the location of as many other places as possible, especially 

 those of interest in connection with all branches of the 

 natural history of the region. All of the old collecting spots 

 that could be traced and located, all of the archaeological 

 and anthropological sites and minor topographical details 

 as springs, etc., have, so far as practicable, been indexed. 



For the purpose of indexing, the original map (41% by 

 46% inches in size) was quartered. 78 The center of the map 

 is at a point not far west of the Massachusetts Avenue bridge 

 over Eock Creek. From that point the territory covered by 

 the map extends approximately lV/ 2 miles to the north and 

 to the south and 10 miles to the east and west. Upon each 

 quarter of the map, squares 23 by 20 in number, have been 

 outlined in red. Each of these units therefore takes in an 

 area approximately % mile square. 



The quarters of the large map are designated by the ini- 



77 Washington and Vicinity. Maryland, District of Columbia, Virginia. 

 U. S. Geological Survey, 1917. 



78 Maps are contained in a pocket attached to back cover. 



