January 20, 1899.] 



/SCIENCE. 



105 



entirely changed, no species, and, so far as 

 he knew, no genus lasting through to the 

 present except that most variable of all 

 genera. Homo, and the species most sensi- 

 tive of all, to phj^sical changes, sapiens. Not 

 only this, but the relics were those of the 

 men, the Digger Indians, living there to- 

 day, and when not bones the objects were 

 those connected with the acorn industry of 

 the present tribes. From all these consid- 

 erations a sweeping argument supporting 

 the general improbability of the geological 

 antiquitj^ of the remains was adduced. 



In discussion W. H. Brewer spoke of the 

 circumstances under which the discovery of 

 the Calaveras skull was made, he hav- 

 ing been at the time on the California Geo- 

 logical Survey. He described its fossilized 

 condition and its contained cemented grav- 

 els and stated his belief in its very consid- 

 erable age even if not Tertiary. He also 

 gave an interesting account of the great 

 theological and ecclesiastical opposition to 

 Professor Whitney that the announcement 

 of the geological age of the skull aroused, 

 amounting almost to persecution. The dis- 

 covery came shortly after the publication of 

 Darwin's views on the descent of man and 

 in the midst of the excitement that these 

 views aroused. 



Major Powell recounted a number of his 

 experiences with discovered relics and the 

 tendency of collectors to palm off modern 

 things as antiquities either in joke or as a 

 fraud. He emphasized the need of depend- 

 ing absolutely on geologists for all reliable 

 testimony as to authentic occurrences in 

 sedimentary deposits. J. A. Holmes spoke 

 in support of the Major's view and related 

 the recently recorded discovery of imple- 

 ments in marl pits and Eocene limestone in 

 North Carolina, the same being attested by 

 affidavits of reputable citizens. 



Geology of the Lake Region of Central America. 

 C. WiLLAED Hayes, Washington, D. C. 



The speaker discussed the following topics, 

 illustrating his remarks by a fine map. His 

 data had been accumulated while in the 

 service of the Nicaragua Canal Commission 

 and especially from test borings: Introduc- 

 tion : general relations of the country under 

 discussion. Toiwgraphy : the coastal plain ; 

 the Chontales hills; the Tola hills; the 

 Costa Eican volcanic range; the Nicaraguan 

 volcanic range; the Jinotepe plateau; the 

 lake basin ; the Eivas plain. ^Climate : the 

 eastern section of heavy rainfall and dense 

 forests ; the western of lighter rainfall and 

 savannahs. Rock formations : Tertiai'y sedi- 

 ments including the older Brito formation 

 and the later Machuca formation ; Tertiary 

 igneous rocks, dacites, andesites, basalts, 

 volcanic breccias and conglomerates; recent 

 sediments, alluvium ; recent igneous rocks, 

 trachytes, basalts, tuffs and pumice. The 

 Regolith : the conditions favor rock decay; 

 the great depth of weathering; red and blue 

 residual clays ; concerning weathering in ig- 

 neous and sedimentary rocks. Recent geologic 

 history of the region: early Tertiary deposition; 

 Tertiary erosion; late Tertiary and post-Ter- 

 tiary uplift and dissection of uplands; recent 

 submergence and alluviation; recent vol- 

 canic activity; formation of lakes and shift 

 of divide to westward. Characteristics of San 

 Juan Valley: the upperflood-plain; the Cas- 

 tillo-Ochoa gorge ; the lower flood-plain. 



The paper aronsed the liveliest interest 

 from the great importance of the project of 

 the international canal. J. E. Wolff asked 

 about the nature of the rock decay and 

 whether silica, the alkaline bases and iron 

 were removed, leaving beauxite, or whether 

 hydrated silicates resulted. Mr. Hayes re- 

 plied that he thought the latter, but that 

 no analyses had yet been made of his many 

 samples. Inquiries were raised about the 

 recency of the volcanic outbreaks and the 

 nature of the lava. The reply was that 

 the lava was basalt and the last outbreak 

 about fifteen years ago. 



