36 



SCIENCE. 



[N. S. Vol. VII. No. 158. 



Incidentally, we remark that it may well be 

 questioned whether the theory of protuberant 

 mountains, so beautifully illustrated in the Sun- 

 dance Hills, is not unduly stretched in attempt- 

 ing to make it cover the Front Eange of the 

 Rockies in Colorado and "Wyoming. Finding 

 the essential condition of eruption iu liquefac- 

 tion by means of relief of pressure, Professor 

 Russell makes the role of steam merely inci- 

 ■ dental. The action of steam is conspicuous 

 enough in volcanic eruptions of the explosive 

 type, but it cannot account for the phenomena 

 of great fissure eruptions ; and the two extreme 

 types of eruption are so connected by fine 

 gradations that the general cause must be iden- 

 tical throughout the whole series. In criticis- 

 ing the special form of the steam theory pro- 

 posed by Shaler, the author justly protests 

 against the enormous thickness of sediments 

 postulated by that theory. Professor Russell 

 holds the steam contained in lavas to be exclu- 

 sively of superficial origin. This is undoubtedly 

 true of a part of it, and probably of much the 

 larger part. But the fluid cavities of plutonic 

 rocks are proof of the existence of water vapor 

 in magmas at great depth, and it appears 

 probable that somewhat of this vapor may have 

 been occluded in the originally molten mass of 

 the globe. Professor Russell holds that vol- 

 canic activity increased through geologic time 

 until the Tertiary, and that it is now declining. 

 This conclusion seems to us not supported by 

 adequate evidence. According to modern views 

 of the mode of solidification of the globe, the 

 reaction of its heated interior upon its surface 

 could not have been very different in Cambrian 

 time from what it is now. The apparent rarity 

 and insignificance of volcanic phenomena in the 

 earlier geological periods may well be explained 

 as due to the destruction of the evidence by 

 erosion and metamorphism, or its concealment 

 beneath masses of superincumbent strata. 



The closing chapter, on the life history of a 

 volcanic mountain, is an exquisite piece of 

 scientific description, in which picturesque 

 imagination gives vividness without detracting 

 from scientific accuracy. One incidental point, 

 however, we should be disposed to criticise. 

 We would not, indeed, contradict the state- 

 ment that it is possible that the aborigines, so 



artistically introduced to add a human interest 

 to the pictures of natural scenery, were living 

 in Tertiary time ; but we do, nevertheless, con- 

 sider such a supposition extremely improbable. 

 The book, so delightful and instructive, would 

 have been made still better by more careful 

 proof-reading. Several proper names are mis- 

 spelled. We read Atria del Cavallo, instead of 

 Atrio ; Mazana, instead of Mazama ; Eoichthofer, 

 instead of Richthofen ; Johnson- Lewis, instead 

 of Johnston-Lavis. In the note on page 74, in 

 which the last name is thus misspelled, the 

 reference to the American Journal of Science 

 should be to Vol. 36. Typographical errors 

 have rendered a few sentences ungrammatical 

 or nearly unintelligible. The printers have 

 also metamorphosed the young insects of Lake 

 Mono into lavie. The book is thoroughly at- 

 tractive in its mechanical execution. Many of 

 the pictures (mostly reproductions of photo- 

 graphs) are very beautiful. 



Wm. North Rice. 



SOCIETIES AND ACADEMIES. 



NEW YOEK ACADEMY OF SCIENCES — SECTION" 



OF GEOLOGY, DECEMBEB 20, 1897. 



The first paper of the evening was by Mr. 

 Arthur Hollick, entitled ' Recent Explorations 

 for Prehistoric Implements in the Trenton 

 Gravels, Trenton, N. J.' Dr. Hollick gave in 

 his paper a summary of the present under- 

 standing of the artifacts found in the Trenton 

 gravels, a more complete statement of which 

 has already been published in Science for No- 

 vember 5, 1897. The second paper of the 

 evening was by Professor J. F. Kemp, entitled 

 ' Some Eruptive Rocks from the Black Hills. ' 

 Professor Kemp summarized the geological 

 features and history of the Black Hills, and 

 gave a bibliography of the works concerning 

 these deposits. He then mentioned the occur- 

 rence of some Leucite-bearing rocks, in the 

 northern part of the hills, similar in character 

 to those which occur in but few other places in 

 this country, as in Wyoming, Montana, Lower 

 California and New Jersey, near the Franklin 

 Furnace. 



Richard E. Dodge, 



Secretary. 



