REPORT OF THE STATE GEOLOGIST. XIX 



portion lying north of the completed line of work of last year — the 33d 

 parallel of latitude. 



I also requested that if possible the United States Geological Survey 

 take up the entire topographic work west of the Pecos River, or if 

 unable to do that, at least to finish the primary tri angulation for us in 

 order that we might take up such detached areas as we desired to study 

 and have accurate connection between them such as this would give. 

 Maj. Powell promised compliance as far as possible, and under date of 

 June 9 writes : 



"It has been arranged that during the field season of 1890 topographic 

 field work will be carried on in the tier of sheets indicated by you, immedi- 

 ately west of the area already mapped — that is, between 99° 30' and 100° of 

 longitude. It is hoped that the maps resulting from this work will prove of 

 service to you. 



" It is not yet possible to indicate what topographic work will be done this 

 year in the Trans-Pecos region. The addition of the irrigation investigation 

 to the work of the Geological Survey has led to the assignment of all topo- 

 graphic work in the region to the Irrigation Survey, and the order in which 

 different districts are surveyed is determined by the needs of the irrigation 

 investigation." 



He also informed me in the same letter that although the United 

 States Geological Survey could not undertake triangulation in Texas 

 as a basis for our own topographic work, the United States Coast and 

 Geodetic Survey was especially authorized by law to co-operate with 

 any State which is conducting a geologic or topographic survey by ex- 

 ecuting triangulation for it. 



Ilaving already been assured by Dr. T. C. Mendenhall of such co- 

 operation as he could give, I immediately wrote him asking that the 

 United States Coast and Geodetic Survey, of which he is the superin- 

 tendent, take up the primary triangulation of Trans-Pecos Texas. In 

 his reply of June 28 he says : 



" In response to your request I will say that we can begin the primary tri- 

 angulation along the boundary line of Texas near the point to which you 

 refer, commencing with your base line if desired, but preferably perhaps at 

 El Paso, and running down the Rio Grande. This triangulation would cover 

 possibly a strip of fifty miles wide, and would furnish you with a number of 

 points and bases from which a local triangulation for topography could pro- 

 ceed. I would endeavor to begin the work during the present season and 

 push it as fast as possible, but the high character of the triangulation de- 



