238 



PHYSICAL GEOGRAPHY. 



where different plans are matched together. These surveys cost over 

 twenty thousand dollars, and their most valuable features are retained in 

 the new draft. 



Maps of the White Mountains by Bond, Boardman, and Guyot. 



Two maps of Connecticut river, referred to on page 46. 



Observations of detail by all who have been connected with the survey 

 from the very first. Some of this has been referred to previously. Efforts 

 have been made constantly to discover and correct every possible error, 

 no matter how minute. 



Maps of several tracts of forest land, particularly of Success, Cam- 

 bridge, Errol, College grant, Carlisle, Pittsburg, Bean's purchase, Waum- 

 bek, Hart's Location, etc., furnished by the proprietors. 



For the delineation of mountain ranges, use has been made of the facts 

 given in the chapter upon Altitudes. 



GEOGRAPHICAL POSITIONS DETERMINED BY THE COAST SURVEY. 



*The geographical positions as given in the earlier reports do not agree exactly with the latest determina- 

 tions, especially of the longitudes. The ocean telegraph has furnished the means of ascertaining more accurately 

 than before the difference in time between Greenwich and Washington. The average correction to be added to 

 the longitudes is 20". 15, and o".28 to the latitudes. In the cases above, that are marked with an asterisk, I have 

 given the latest figures of the Coast Survey, but have not corrected any of the others. 



