516 Reviews — Delesse et De Lapparent, Revue de G^ologie. 



examination and accurate description of those which, fell under his 

 observation, instead of rushing into print with a crude classification 

 of rocks founded on imperfect data, and an ambitious Cosmical 

 theory, the ideas of which are culled from the works of other 

 geologists, not often referred to, with which the remainder of his 

 memoir is filled. No doubt the earlier manifestations of volcanic 

 energy along the entire north-west coast-range of the two Americas 

 would amply repay an accurate and close examination, undertaken 

 on separate points by competent geologists. 



Mr. Darwin,^ long since reported, as the result of his examination 

 of a section across the South American Continent, that the geo- 

 graphical area east of the Andes, must have once consisted of 

 metamorphic schists, clay-slates, and plutonic rocks, forming the 

 floor of the ocean, which were then covered by vast streams of lava 

 (trachytic, and greenstone porphyries), together with alternating 

 piles of angular fragments of similar rocks — all ejected from sm6- 

 mariitie volcanos, and apparently, from the compactness of the rocks, 

 80 formed in deep water. This volcanic formation was subsequently 

 covered by gypseous deposits of the age of our Chalk, mingled with 

 the products of contemporaneous volcanic eruptions. And in some 

 points, especially in Chili, these beds were again loaded, in the latter 

 Tertiary period, with a vast pile of volcanic submarine tufis and 

 lavas, previous to the final elevation of the continent above the 

 water level, or the opening of the great sub-aerial volcanic range of 

 the existing Cordilleras. 



Surely this is a far more intelligible account of the relations 

 between the several hypogene and sedimentary rocks of America 

 than can be gathered from the confused and inconsistent statements 

 of MM. Humboldt, DoUfus, or Eichthofen, Let us hope that some 

 painstaking geologist like Mr. Darwin, with a judgment unwarped 

 by prepossessions in favour of the absurd elevation-crater theory, 

 will, before long, extend his observations to other portions of the 

 great western Continent, and communicate to the public his detailed 

 description of these interesting relations.^ 



Gr. P. SCROPE. 



II. — Kevue de Geologie, pouk les annees 1866 et 1867. Par 

 MM. Delesse et De Lapparent. Paris, 1869. 



WITH each succeeding year the progress of Geology, like other 

 sciences, naturally accumulates so many new facts and obser- 

 vations, and these are distributed through so many periodicals, and 

 in dijfferent languages, that it is very difficult for the student to keep 

 himself fully acquainted with the increased knowledge or continued 

 additions to the science. A useful resume, like the work before us, is 



* Darwin's S. America, p. 237. 



^ Such a description will probably be in part found (by those who have the oppor- 

 tunity of consulting it) in the report of Dr. J. S. Newberry to Con.oress, published 

 1861, of his geological observations while employed on the expedition for exploration 

 of the Rio Colorado, in 1857-8, of which I find a notice in page xlii. of Mr. Bell's 

 " New Tracks in North America," just published by Messrs. Chapman and Hall. 



