160 



SCIENCE. 



[Vol. VII., No. 159 



term ' caldera ' is proposed and used as a general 

 name for volcanic orifices of the Hawaiian type. 

 As the column of lava gradually melts away the 

 enclosing rocks, the caldera is enlarged by the 

 falling-in of the surface, and it is not in any case 

 due to explosions. Mauna Loa and Kilauea are 

 clearly independent volcanoes ; and we have no 

 reliable indications that their activity is diminish- 

 ing. The vast antiquity of the Hawaiian volca- 

 noes is plainly shown, not only by their magni- 

 tude, but also by the wonderful progress of the 

 agents of erosion, especially in those islands where 

 the volcanic fires are now extinct. This is one of 

 the principal topics discussed in the chapters on 

 Maui and Oahu. 



The abstract of the report by Mr. J. S. Curtis on 

 the mining geology of the Eureka district, Nevada, 

 supplements that by Mr. Arnold Hague on the 

 general geology of the same district in the pre- 

 ceding volume. It is accompanied by sections of 

 the principal workings, and discusses exhaustively 

 the characteristics and probable origin of these 

 singular ore-deposits, which had yielded sixty 

 millions of dollars up to the close of 1882. 



Following this is a short but useful chapter on 

 popular fallacies regarding precious metal ore- 

 deposits by Mr. Albert Williams, jun. Dr. C. A. 

 White's review of the Ostreidae of North America, 

 with an appendix by Mr. Heilprin, and thirty- 

 eight plates, describes in simple yet scientific 

 language all the known fossil species and the 

 single living species of the Atlantic coast. A 

 second appendix by Mr. Ryder, with eleven 

 plates, is devoted to an interesting sketch of the 

 life-history of the oyster. 



The volume concludes with Mr. I. C. Russell's 

 geological reconnaissance in southern Oregon, 

 with two maps and sixteen small sections. This 

 is a short but highly interesting account of the 

 extreme northern part of the Great Basin, which 

 is shown to possess the same structural and 

 climatic features as the basin of Lake Lahontan, 

 which bounds it on the south, and was described 

 by the author in the annual report for 1881-82. 



GEOGRAPHICAL NOTES. 



Missionary maps. — The establishments of Les 

 missions catholiques at Lyon, France, have issued 

 an atlas containing data collected by the Catholic 

 missionaries in various parts of the world. Beside 

 the general maps, which resemble those of any 

 good elementary atlas, there are some thirty de- 

 tailed maps which have appeared from time to 

 time in the organ of the missionary bodies. 

 Numerous important additions to geography have 

 been made by the missionaries ; and, in bringing 



them together in convenient form, the atlas meets 

 a real need. They appeared first in German, with 

 explanatory text by Father O. Werner, and have 

 been translated into French, with additions, by 

 Valerien Groffler. 



A newly discovered affluent of the Kongo. — 

 The despatches from the Cape of Good Hope state 

 that the expedition under Lieutenant Wissmann 

 has discovered a new affluent of the Kongo, which 

 will have an important bearing on the opening-up 

 of the lower Kongo basin. Wissmann is on his 

 way to Europe with the details. The new river is 

 a powerful stream, over five hundred miles in 

 length, between the equator and Stanley Pool. It 

 is eight miles wide at its mouth, and quite deep. 

 There were no obstacles to its navigation and the 

 Pogge Falls, in the Tapende country, latitude 6° 

 south, and longitude 22° east. Lake Lincoln, to 

 be found on some charts, does not exist : the only 

 lake encountered was Lake Leopold II., near the 

 Kongo. The journey was made in large canoes 

 constructed by the expedition, and a way was 

 forced through the territory of savage cannibal 

 tribes, who, if armed with guns instead of arrows, 

 would have prevented their passage. In a single 

 day as many as five conflicts took place, and sev- 

 eral of the party were wounded, though none were 

 killed. The journey was accomplished by Lieuten- 

 ants Wissmann and Mtiller, a physician, artificer, 

 and forty-six natives. The ferocity of the natives 

 is accounted for by the fact that they had never 

 seen white men or fire-arms. More details will 

 soon be accessible. Meanwhile it seems more 

 likely that the river is one of those which have 

 been known only by report, rather than an entirely 

 new discovery. The country is reported to be 

 fertile, producing palm-oil, sugarcane, rice, and 

 other tropical products. 



Explorations in Central South America. — De 

 Brettes sends a short note on his recent travels in 

 the unexplored part of the southern district of the 

 Gran Chaco, which began last March, and lasted 

 forty-four days. He discovered a large salt lake 

 (along which his party travelled nine days, and the 

 west shore of which is estimated to be one hun- 

 dred and thirteen miles long), also three rivers, 

 running in a northerly direction, supposed to be 

 tributaries of the Rio Vermejo. The south Chaco 

 is flat, covered with thorns, mimosas, and tall 

 herbage. The natives are hypocritical and cruel, 

 and live in utter barbarism. After penetrating 

 two hundred and twenty miles into the unknown 

 region, the explorers were obliged by fever to re- 

 trace their steps to Corrientes. A new expedition 

 was in contemplation. 



Restoration of Lake Moeris. — The investiga- 

 tions of Mr. Cope Whitehouse in regard to the 



