EEPORT OF THE SECRETARY. 51 



of yellow sandstone outcrops, which is fossiliferous, the bivalves of the 

 geuus TJnio being very numerous. 



The work of Mr. Henshaw, collector in zoology, was mainly confined 

 to the vicinity of Carson City, Nevada, and the region contiguous to 

 Lake Tahoe. In the character of its avian fauna the pine region of the 

 eastern slope of the Sierras was found to nearly resemble that of the 

 western side, and some birds, distinctively Californian in nature, were 

 ascertained to range down to the foot-hills on the borders of the sage- 

 brush plains of Nevada. 



The fish of the various streams and lakes of this well-Watered region 

 received careful attention, and extensive collections were made. Speci- 

 mens of such insects as remained at this late season were collected, and, 

 though the results are not large, it is more than probable that they in- 

 clude a number of novelties, especially among the Orthoptera. 



The section of country visited will prove of most value for timber, 

 grazing, and mineral purposes, as in most instances the altitude of the 

 high interior mountain-ranges precludes the certainty of crops, even 

 where there is arable ground. In favorable exception to this rule, how- 

 ever, may be noted the land iu proximity to Honey Lake, in the north- 

 ern part of the California area, and on either side of the Rio Grande, 

 below Albuquerque, in New Mexico. 



An important feature of the present stage of the survey results from 

 the instructions which require each chief of party or topographer to 

 take notes sufficiently detailed to permit the plotting, upon resource- 

 sheets, of the limits between arable, irrigable, grazing, mining, and timber 

 lauds, indicating, also, those absolutely barren. In the office, in addition 

 to the regular geographical atlas-sheets, certain preliminary maps have 

 been arranged, from which will be prepared colored sheets, upon which 

 areas will be so delineated as to readily convey to the eye the general 

 capabilities of the section embraced. These delineations, together with 

 the tabulated results of the season's observations, will give a complete 

 account and almost perfect idea of the natural resources of the country 

 and its availability for agricultural, mining, and grazing purposes, and 

 will graphically separate the arid, barren, and otherwise worthless tracts 

 from the better land. In future operations it is intended to procure 

 complete statistics on these important points, and the material of former 

 years having been digested, the comparison of large areas will then be 

 practicable. In addition to the data disclosing the natural resources, 

 the direction of drainage, with basin perimeters, will be indicated, and 

 the amount of rain-fall determined as nearly as practicable. The sheets 

 and tables will then furnish fair data for deciding upon the feasibility 

 of irrigating by canals, reservoirs, and artesian-wells. These maps will 

 be completed as rapidly as the limited force and relative importance of 

 different portions of the work will allow. 



Through an inadvertence on page 56 of the Annual Report of the In- 

 stitution for 1875, it is stated in relation to geographical surveys west 



