72 Notices respecting JYew Books. 



which has brought the land to its present form. The various 

 forms of rock- weathering are discussed as derived from the study 

 of tombstones (Essay A'iii.); and the effects of modern atmospheric 

 action, conjoined with the bedding and jointing of rocks, are shown 

 in the isolated pillar of Old Eed Sandstone, 600 feet high, standing 

 out from the mainland of which it once formed a part, and known 

 as the " Old Man of Hoy " (Xo. I.). 



The power of rain- and river-action is fully shown in the deep 

 gorges excavated through the basalt and other rocks of the 

 Auvergne and Haute-Loire of Central France (Xo. Y.) ; but great 

 as has been the efficiency of superficial erosion on the development 

 of the terrestrial surface of Europe, the author considers that the 

 fundamental laws of denudation can nowhere be better learnt than 

 in the western region of the Rocky Mountains, the evolution of the 

 mountain-forms of the Uintah range, the high plateaux of Utah, 

 and the great basin of the Colorado, where " the proofs of enor- 

 mous superficial waste rise to such a gigantic scale as wholly to 

 baffle every observer who has yet attempted to describe them" 

 (1>. 229). 



In the essays on the Volcanoes of Central Prance (Xo. V.), the 

 Yellowstone Geysers (Xo. X.), and the Lava-fields of Xorth-west 

 Europe (Xo. XL), are many interesting and suggestive remarks on 

 volcanic phenomena. The study of the former seemed to throw 

 light on the character and aspect of the Carboniferous volcanos of 

 Central Scotland (p. 102). Again, there were features of former 

 volcanic action on which the phenomena of modern volcanos ap- 

 peared to afford but little light; "in particular, the vast number of 

 fissures which in Britain had been filled with basalt and now formed 

 the well-known and abundant ' dykes,' appeared hardly to connect 

 themselves with any known phase of volcanism" (p. 276). This 

 has been accounted for by the emission of vast floods of lava, 

 " massive eruptions," without the formation of cones or craters — a 

 view advocated by Richthofen more than twelve years ago, — and 

 that our modern volcanos, Vesuvius and Etna, present us by no 

 means with the grandest type of volcanic action. Dr. Geikie, after 

 his visit to the lava-fields of the Pacific slope, was enabled to rea- 

 lize the conditions of volcanism described by Richthofen, and thus 

 assist in solving a difficulty he had long felt in accounting for the 

 extent of the dykes and other protrusions of basalt, " which can be 

 traced over an area of probably not less than 100,000 square miles 

 in Britain"; for they occur from Yorkshire to Orkney, and from 

 Donegal to the mouth of the Tay " (p. 276), which was only part 

 of the far more extensive region that included the Faroe Islands 

 and Iceland. 



These stupendous outpourings of lava in the west of Scotland, like 

 those on the plains of Idaho, are considered to be due to the fissure 

 or " massive " type of eruption ; and that the basaltic plateaux of 

 Abyssinia and the " Dec-can traps " of India probably mark the 

 sites of some of the great fissure-eruptions which have produced the 

 lava-fields of the Old "World (p. 285). 



