496 



SCIENCE. 



[N. S. Vol. III. No. 66. 



harder ledges and broader divides as rem- 

 nautal ranges ; while the incongruity of the 

 modern waterways indicates that, after as- 

 suming this general configuration, the tract 

 was tilted southwestward in such manner 

 •as to stimulate the streams flowing in this 

 ■direction and paralyze those flowing north- 

 eastward, and thus to produce a general 

 migration of divides. These indications 

 may perhaps be misleading, or may have 

 been misinterpreted ; and the abrupt tran- 

 sition from rugged mountain slope to planed 

 base-level is an attendant feature which re- 

 quires explanation before the interpreta- 

 tion can be regarded as final. The re- 

 searches relating to this subject are not 

 ■complete, but both Mr. Willard D. John- 

 son, of the later expedition, and the writer 

 have collected data bearing on the subject. 

 Among other data maj' be mentioned an 

 admirable section exposed along the gulf 

 shore from Kino bay to San Miguel point 

 (some 20 miles), in which the relations be- 

 tween rugged range, planed base-level, and 

 torrential plain are clearly shown. 



Mr. Johnson carried forward a planeta- 

 ble survey throughout Papagueria and Seri- 

 land, which will not only yield the first 

 trustworthy map of the region, but will 

 serve as a basis for the representation and 

 interpretation of the geology. * 



METEOROLOGY. 



Throughout the expeditions of 1S94 and 

 1895, noninstrumental observations were 

 made on winds, clouds, precipitation, frosts, 

 etc., and noted with considerable care, with 

 the view of determining the influence of 

 these elements of the weather on geologic 

 process, on the flora and fauna, and on the 

 human population, native and introduced. 

 These notes, made incidentally at a con- 

 stantly shifting base and for short periods 



* A preliminary impression of the Seriland portion 

 of the map will appear in The National Geographic 

 Magazine for April, 1896. 



only, would be of little value in a region 

 adequately supplied with meteorologic sta- 

 tions, but acquire some value from the dearth 

 of observations in the district to which they 

 pertain, particularly since this district aids 

 in shaping the weather conditions prevail-, 

 ing over a considerable area in southwest- 

 ern United States. Prof. Cleveland Abbe 

 has signified a desire to publish the notes 

 in an early number of the Monthly Weather 

 Revieiv of the United States "Weather Bu- 

 reau, and the material will thus be made 

 accessible to meteorologists. The notes ac- 

 quire value also from the close relation be-, 

 tween weather and life in this region. 



It may be observed in brief that the chief 

 weather characteristic of the region is arid- 

 ity, the rainfall being limited in quantity 

 and irregular in distribution ; there are two 

 nominally rainy seasons, in July-August 

 and January-February, respectively, but 

 rains sometimes occur at other times, whUe 

 precipitation often fails during these sea- 

 sons ; but whether rain falls or not, these 

 are seasons of greater or less humidity of 

 the air, so that the flora is vivified semi-an- 

 nually, whereby many species are undoubt- 

 edly enabled to survive the seasons of 

 drought. The second weather characteris- 

 tic is heat, especially at lower altitudes ; the 

 summers are oppressive for men and ani- 

 mals, the winters no more than pleasantly 

 cool — the weather in Seriland may be in- 

 ferred from the fact that, while these In- 

 dians have words for rain and hail, they 

 liave none for ice, snow, or frost. Another 

 characteristic is the dearth of clouds, and 

 the consequent intensity of light and fervid- 

 ness of insolation by which the skins of men 

 and animals are undoubtedly, and the habits 

 of certain plants apparently, afiected. To- 

 ward the coast, fogs are not uncommon in 

 the autumn, and are said to occur at other 

 seasons ; this weather condition appears to 

 afiect the flora for 10 to 50 miles inland, 

 according to the local configuration. The 



