REPORT OF CAPTAIN HUMPHREYS TO THE SECRETARY OF WAR, 1856. 
31 
long, and a descending grade of 106 feet per mile for 12 miles would be required. A better pass 
was reported, but again the want of an escort prevented the necessary examinations. 
A recent survey made by a number of gentlemen from Shasta to determine the practicability 
of constructing a wagon road from Shasta valley to Fort Reading, by the valley of the Sacra¬ 
mento river, showed that project to be quite feasible. This route was not examined owing to 
the lateness of the season, there being no grass upon it at that time, and the animals being 
nearly broken down. The Trinity trail, which crosses Scott’s mountains and Trinity mountains, 
was followed, and it proved utterly impracticable for a railroad. 
By the return route the distance from Vancouver to Fort Reading is 470 miles. 
Of the two routes surveyed from Benicia to the Columbia river, that east of the Cascade range 
may be considered practicable for a railroad. Three hundred and fifty miles of it lie through a 
fertile and settled region, where the construction would be easy. Two hundred miles are 
through an unsettled and barren country, but where no very heavy work would be required. 
The remainder of the route, which side locations would probably render 250 miles long, passes 
through a wilderness, and would require difficult and costly construction. 
By the actually surveyed line west of the Cascade range, there are 500 miles where the con¬ 
struction would be easy, 100 miles that would be difficult and expensive, and 80 miles imprac¬ 
ticable. 
The field work terminated at Fort Reading, the season being too far advanced to admit of 
the intended exploration of the Sierra Nevada near the sources of Carson river. 
Lieut. Williamson and party reached Washington in January, 1856, and have since been 
engaged in preparing the maps, drawings, and detailed reports of the survey. These are now 
in an advanced condition. 
The party, under the direction of Captain John Pope, Topographical Engineers, organized by 
the instructions of the Department of January 5, 1855, to ascertain the practicability of con¬ 
structing artesian wells upon the arid plains of Texas and New Mexico, has continued its labors 
during the past year. The region selected for the field of its first operations is described by 
Captain Pope as extending from the Rio Grande, east, to the headwaters of the Canadian, the 
Red river, the Brazos, and the Colorado, with their tributaries. It is included between the 
parallels of 30° and 36° N. latitude, and comprises an area of about 100,000 square miles. The 
river Pecos flows through it in a general S.S.E. direction, dividing it into two nearly equal parts. 
Three chains of mountains, generally parallel, averaging 3,000 feet above the plain and about 
fifty miles apart, lie to the west of the Pecos, the easterly range (called at the crossing of the 
32d parallel the Guadalupe mountains) being fifty miles distant from that river. The strata of 
the valleys between these chains have been broken through by the upheaved mountains, and 
the ruptured edges lie along their sides at altitudes from 600 to 2,000 feet above the lowest lines 
of the basins between. From the notes accompanying the meteorological observations, it 
appears that the amount of precipitation for the year in rain and snow is from four to five times 
as great upon the mountains as it is upon the plains. Descending upon the summits, it is shed 
along the faces of the hard rock until it reaches the upturned edges of the broken and porous 
strata, through which it percolates. The water is thus intercepted from running over the 
country below, and forms reservoirs beneath the earth, which, if reached by boring at any point 
lower than the source, must rise and overflow the surface of the ground. The division of the 
region referred to lying east of the Pecos is a vast undulating prairie, called the Llano Estacado, 
or Staked Plain. It is a table land, about 3,500 feet above the level of the sea, with a dip 
