328 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the 100th Meridian," during the last season was composed of 

 nine main parties and three astronomical parties, which oper- 

 ated in the States of California, Colorado, Nevada, Oregon, 

 and Texas, and Arizona, New Mexico, and Washington Ter- 

 ritories. Forty-six observers took the field, leaving a small 

 force at the Washington office engaged in the preparation 

 of maps and reports. The astronomical parties in charge of 

 Professor T. II. Safford at the Ogden Observatory, Mr. J. 

 H. Clark in the California section, and Mr. Miles Rock in 

 the Colorado section, made observations at Walla -Walla, 

 Washington Territory ; the Dalles, Oregon ; Fresno, Califor- 

 nia; Fort Bliss, Texas; and Fort Bayard, New Mexico, con- 

 necting with Ogden as the initial meridian. 



In California, topographical parties occupied points in the 

 Cascade Mountains and ranges to the eastward within the 

 great interior basin extending towards the Blue Ridge, re- 

 connoitring a large area. Operations were carried south- 

 ward from Lake Tahoe along the Sierra Nevada, one party 

 occupying the White Mountain range and connecting with 

 the triangulation which joins the astronomical station at Aus- 

 tin, Nevada. A contour survey of the Washoe mining re- 

 gion was completed, and numerous details gathered relating 

 to the operations of the vertical and meridional sections of 

 the lodes. 



Work for completing the topography of the section be- 

 tween the Sierra Nevada and Cascade ranges was also car- 

 ried on. From the southern end of the Sierra Nevada a par- 

 ty transferred from the Utah section connected with the 

 work of 1875 from Los Angeles east and north, and operat- 

 ed along the coast range to lat. 30 30' N. 



In Colorado, one party, following the Rio Grande north- 

 ward, filled in details of new routes of communication and 

 of incomplete meanders, and was further employed upon de- 

 tailed work. A detachment meandered north and westward 

 from the Rio Grande at Los Lanos, opposite Fort McRae, 

 through the basin of the Little Colorado to Camp Apache, 

 Arizona, and thence eastward again to the Rio Grande, mak- 

 ing meanders of considerable precision along three natural 

 routes of communication from the drainage basins of the 

 Gila Salt River and Colorado Chiquito to the Rio Grande. 



Another party extended the triangulation southward to 



