250 GROVE KARL GILBERT— DAVIS [Memoirs [ vo A l t xxi ! ; 



Before the Geological Society of Washington Gilbert spoke twice on Alaskan problems; 

 the "Morphology of southern Alaska" in 1901 and the "Statics of a tidal glacier" in 1903; 

 in 1901 he had presented to this society some "Petrographic and geologic notes on western 

 Utah," this being one of his few statements concerning the field season of that year among the 

 basin ranges, here treated in a separate section; unfortunately not even an abstract of these 

 notes was published. He presented before the same society several papers embodying the 

 results of special studies in the Sierra Nevada which were also communicated elsewhere; in 

 1908 he gave an account of his "Hydraulic laboratory at Berkeley," and a year later repeated 

 here the presidential address on "Earthquake forecasts" which he had delivered to the 

 Association of American Geographers at Baltimore shortly before. 



At the winter meeting of the Geological Society of America in Rochester, December, 1901, 

 he gave a short paper on "Joint veins," a subject suggested by a body of shattered rock found 

 the previous summer at the foot of one of the basin ranges ; a year later in Washington, on New 

 Year's Day, 1903, he presented his reasons for still holding to the view that the basin ranges 

 are uplifted and dissected fault blocks, in spite of an adverse interpretation that had been 

 published a few years before; but this important communication is represented only by a nine- 

 line abstract in the society 's bulletin. The interpretation of the basin ranges that he adopted 

 is discussed in an earlier section of this memoir. At the St. Louis meeting, in December, 1903, 

 he presented Louderback's essay on the Humboldt Ranges, in the absence of its author. 

 Reference to his second election to the presidency of this society for 1909 is made below. 



Residence in California for parts of a series of years brought various new problems to Gil- 

 bert's attention, as will be detailed in other sections; it also gave him opportunity of attending 

 several meetings of the Cordilleran section of the Geological Society of America; in 1905 

 he presented there three papers on Sierra Nevada, which he gave also before the Geological 

 Society of Washington, as above; and the next year he described the "Transportation of debris 

 by the Yuba River," a chapter from his long Californian study of the outwash of debris by 

 hydraulic mining in the mountains. In 1907 he was elected a counsellor of the Cordilleran 

 section. In the same year he lectured to four different audiences in California on the "Salton 

 Sea," which had been then produced in the southern part of the State by an overflow of the 

 Colorado River into a depression, once the head of the Gulf of California, but later inclosed 

 by the river delta and evaporated to dryness in the arid climate there prevailing. A reference 

 to a Powell-Gilbert essay on this temporary sea has been made in an earlier section. 



Gilbert attended the meetings of the American Association for the Advancement of 

 Science only on two occasions after 1900; first in Washington in the winter of 1902-3, when 

 he spoke before the geological section on " Physiographic belts in western New York" and on 

 "A viscous rhyolitic eruption," and again at the end of 1903 in St. Louis, when he told of 

 "Domes and dome structures in the Sierra Nevada." 



It was a good fortune for the National Geographic Society that Gilbert was its vice 

 president in 1904, as he was therefore available to greet the members of the International 

 Geographical Congress in the name of the society when they assembled in Washington in 

 September of that year. He addressed the congress on the "Sculpture of massive rocks," accom- 

 panied its peripatetic passage to Niagara, where he served as local guide and gave an evening 

 address on the evolution of the falls, and then went to St. Louis, where he spoke before the 

 Congress of Arts and Sciences gathered at the World's Fair on "Asymmetry of mountain 

 crests in the Sierra Nevada." 



The handful of teachers of geography who founded the Association of American Geogra- 

 phers in 1904 were gratified to include Gilbert among their original members: he was elected 

 their first vice president in 1905 and their president in 1908. The Association was thus so 

 fortunate as to hear from him a presidential address on "Earthquake forecasts," at the meeting 

 in Baltimore, January 1, 1909, which made so favorable an impression that he was asked to 

 repeat it later in the same month before the Geological Society of Washington and the National 

 Geographic Society of the same city. This thrice-presented address, one of the most inter- 

 esting that Gilbert ever wrote, was the last he delivered in public ; it is here analyzed in another 

 section. 



