The question of irrigation along the upper Rio Grande being one of great importance to the citizens of El Paso County and to the State generally, it was decided that an examination of the soil and water of that section should be made in order that there might be proper data from which to discuss the feasibility of irrigation should a suitable dam be built above El Paso. Prof. H. H. Harrington, of the Agricultural and Mechanical College, was selected to make the investigation, and in the report herewith submitted he gives the results of his work.

To this is added a like discussion of the soils of the Pecos Valley and water of the Pecos River. These specimens were collected under the instructions of this department by Mr. B. K. Brant, and represent the characteristic soils of that region.

The results show clearly the absolute necessity for just such investigations as are here recorded. The examination of the soils of the Rio Grande and Pecos valleys proves that they are equally fertile and that both need only the requisite supply of suitable water to render them highly productive.

Irrigation has been carried on for years on the Rio Grande, and the results obtained in practice fully corroborate those brought out by the chemical analyses of the water of that river as regards its entire suitability for irrigation, if it can be obtained in proper quantity.

Preparations are now being made to use the water of the Pecos River for irrigating the lands lying in the valley. The analysis of this water shows that it contains so large a quantity of salt as to make it advisable to proceed with the utmost caution in this work. It is true that salt, being readily soluble in water at all temperatures, would be carried off to a greater or less extent by the rains falling upon the soil during the year, but it would seem rather a dangerous experiment to put the amount of salt as shown upon soils already amply supplied with alkaline material, even with all the possibilities of its being leached out again by later rains. The danger is more fully shown if we take into consideration the existence of such spots as are described under soil specimen No. 4, which offer strong proof that the rainfall is entirely insufficient to accomplish a work of this kind.

The results of the analyses of the Pecos water are fully verified by the report of Mr. C. C. McCulloch, Jr., of this Survey, who made a personal examination of the river and new canal. He says: "The banks of the river are lined with incrustations of salt left by the evaporation of the river water, and present a very white appearance to the eye. The sides of the canal are