404 NOTICES OF NEW BOOKS. 



molluscs, and the remains of fishes with rhomboidal enamelled scales are found 

 in the ancient coal formations ; colossal skeletons of crocodilian animals and the 

 long-necked Plesiosaurus, together with various shells belonging to other groups 

 of Cephalopoda, and the remains of Cycadasaceous plants occur in the rocks of 

 the oolitic period ; other not less strange and varied forms are met with in the 

 chalk, some of them, however, approaching more nearly to existing species ; 

 while extensive masses of fossil remains of infusorial animalcules, whose history 

 has been made known to us by the microscopical discoveries of Ehrenberg, are 

 exhibited in the various beds of newer date, known as polishing slate, semi- 

 opal, &c. ; and the bones of the hysena, the lion, and numerous elephantine 

 pachyderms are strewed over the floors of caverns, or are covered up by the most 

 recent deposits of mud and diluvium. In proportion as our knowledge of other 

 natural phenomena becomes more complete, these marvellous productions cease 

 to be mere objects of curiosity and wonder, and they become, as they deserve to 

 be, the source of earnest and deep consideration. — pp. 26 — 28. 



In his general sketch of cosmical phenomena, our author, as might 

 perhaps be expected, devotes a considerable proportion of his space 

 to a description of astral and planetary phenomena, and the meteo- 

 rological discussions that arise out of such considerations. In 

 passing thence to the actual crust of our globe, he alludes (p. 166.) 

 to the calculations that have been made as to the extent of our 

 knowledge on this subject derived from geological considerations, 

 and also recurs to the question of subterranean temperature. 

 After a somewhat detailed account of the determination of the 

 form of the earth, its mass, and other physical characters, the sub- 

 ject of earthquakes and volcanic disturbances is introduced ; and 

 here the great and varied knowledge of the author on a subject 

 of late but too little studied is admirably exemplified. We can- 

 not, however, find space for any extended quotation, and without 

 such the nature of the argument in this part could not be fairly 

 judged of; but we may refer the reader who is interested in this 

 subject to the original (see p. 210. et seq.), where he will find much 

 important and some new information. The subject of gaseous 

 eruptions and of cold and warm springs succeeds the consideration 

 of the other more terrible marks of volcanic and deep-seated 

 action, and a few remarks are added on mud volcanoes before 

 proceeding to the consideration of the distribution of active vol- 

 canic centres on the earth's surface. 



Passing on then to the more geological considerations relating 

 to volcanic phenomena and igneous rocks generally, it becomes a 

 matter of interest to the English geologist to learn the views of so 

 well-informed a writer with regard to igneous geology. We make 

 no apology therefore for quoting a page or two from this part of 

 the work before us, and the more so since M. de Humboldt's 

 views of the geology of fossiliferous rocks are not given in any 

 detail, and need not detain us, offering nothing that is at all new 

 to the English reader. The following account of granitic rocks 

 will, we think, be read with some interest. 



Granite and syenite are of very different geological ages, the date of 

 formation of the granite penetrated by syenitic veins being more modern than 

 that of the elevating disturbing force. The surface of insulated granitic masses 

 of ellipsoidal shape, whether in the Hartz, in Mysore, or in Southern Peru, is 



