EDITORIAL 179 



is an extensive formation of gray sandstone which attains a thick- 

 ness of several hundred feet and is very porous. It slopes gently 

 toward the Atlantic and pure water flows from it in outcrops near 

 the coast. The head of water in these strata is unknown. Farther 

 south in Patagonia the central sierra is replaced by plateau country 

 and in Comodoro Rivadavia, in latitude 46 near the coast, wells 

 which were sunk by the government in search of water developed 

 petroleum. There is a large area in this region in which the 

 geologic structure and the possibilities of artesian water need to be 

 developed. In the great plains east of the Andes there are glacial 

 deposits which may furnish superficial supplies like those of the 

 Dakotas, and the marine Tertiary and Mesozoic strata afford con- 

 ditions not unlike those of southern California. Here as well as 

 in the valleys among the spurs of the Andes from Patagonia to 

 Bolivia the geological structure is complicated and the problem 

 of artesian water is one of peculiar difficulty as well as of great 

 interest. 



Our present knowledge of these conditions rests upon recon- 

 naissance work and the stratigraphic and paleontologic observa- 

 tions of the Geological Survey of Argentina. No work based 

 upon topographic maps and systematic structure has as yet been 

 undertaken. The problem is therefore one whose elements are as 

 yet to be developed. The Argentine government is using every 

 means to encourage settlement and development of the rich agri- 

 cultural regions which lie in the zone of sufficient rainfall east of the 

 Andes, and also the vast grazing district of Patagonia. In order 

 to afford ready communication it is building railroads at great 

 national expense and operating them. The need of pure water 

 for locomotive use as well as for other purposes has thus been made 

 critically evident, and the minister of public works, Sehor Ramos 

 Mexia, has adopted a plan for making surveys for the determina- 

 tion of artesian water conditions along the lines of national rail- 

 ways. He contemplates topographical and geological surveys of a 

 character similar to those executed by the United States Geological 

 Survey, from which he derived the initial suggestion. He last 

 summer applied to the United States government for the services 

 of a geologist and such assistants as he might need, and our govern- 



