252 PHYSICAL GEOGRAPHY. 



Summarized, the altitudes are these : 



Difference. Altitude. 



Newmarket Junction, 51.916 



Manchester, -f-138.916 180.832 



Concord, -f-71.565 252.397 



White River Junction, +116.840 369.237 



Connecticut lake, +1249.626 1618.863 



From South Ashburnham, Mass., through Bellows Falls, to 



White River Junction. 



A second reference line, connecting with the one already described at 

 White River Junction, was obtained from Boston by way of Fitchburg 

 and South Ashburnham, Mass. The height of the railroad at the latter 

 place, as determined by the Fitchburg and Cheshire Railroad surveys, was 

 obtained from the records of the Cheshire Railroad ; and the profile of 

 that road was used to Bellows Falls, through the kindness of R. Stewart, 

 superintendent. From this place the remaining distance to White River 

 Junction was levelled over for the geological survey by Warren Upham, 

 assisted by Benj. P. Kelley, in February, 1874. The height of White 

 River Junction thus obtained was 32 feet above that from the former 

 series. In the list of altitudes upon this series, all heights, from White 

 River Junction to Troy inclusive, are given to agree with the previously 

 determined height of White River Junction, while those south of this 

 point agree with the assumed height of South Ashburnham, this 

 arrangement being adopted because of a slight discrepancy, amounting 

 to nearly this correction, found to exist at that point in the Cheshire Rail- 

 road profile. With the change which would be justified by a more favor- 

 able interpretation of the profile at this place, the series from South 

 Ashburnham gives White River Junction 12 feet higher than by the 

 series from Concord. Another survey over part of this route, in March, 

 1874, by R. S. Howe, to connect his levels from Concord, over the Con- 

 cord & Claremont Railroad, with those from the same place over the 

 Northern Railroad, proves by almost exact agreement the entire correct- 

 ness of this work north from Claremont Junction. 



Levels had been already obtained, under the direction of the geological 

 survey, from South Vernon to Bellows Falls, by Gyles Merrill, Jr., in Feb- 

 ruary, 1873, and the completion of this work to White River Junction 



