Progress of Geology. 247 



Italian writers. In this way our still youthful science seems to 

 be completing the grand tour of Europe. The literary history 

 and the natural history of this part of the subject are equally 

 curious ; and these are, one and the other, admirably treated of 

 by Mr Lyell, who has, by singular good fortune, skill, and in- 

 dustry, both collected a mass of new and important facts with 

 regard to this fourth class of strata in Italy, and also brought 

 into notice a number of very remarkable geological books and 

 authors, hitherto little known and heard of, at least in this pari 

 of the world. — Wheicell. 



2. Werner according to Ciivier, Lyell, and MacCulloch. 



(1) Werner according to Cuvier. — The earth, in fact, is com- 

 posed of mineral masses, and modern observers have satisfied 

 themselves, that these masses are not thrown together at random, 

 Tallas, during his laborious travels to the extremity of Asia, had 

 remarked that their superposition could be referred to fundamen- 

 tal laws. Sau^sure and De Luc in traversing in many directions 

 the most elevated mountain-chains of Europe, had confirmed 

 their joint observations. Werner, without quitting his own 

 country, has carried the knowledge of these laws to its utmost ; 

 and he has been able to read, in the laws, the history of the 

 revolutions of which they are the work. 



Tracing every bed throughout its whole length, without per- 

 mitting himself to be led astray by the interruptions which di- 

 vide it, by the mountain crests and different elevations which 

 arise above it, he has determined in some degree the different 

 ages, and the age of all the accessory matters which are inter- 

 mingled with the principal substances. 



The different fluids by which the globe has been surrounded^ 

 —the changes of their composition,— the violent movements by 

 which each change has been accompanied ;— all of these have 

 been found, written to his eye, in the monuments which they 

 liave left. 



A universal and tranquil ocean deposites, in great masses, 

 the primitive rocks,— those rocks which are distinctly crystal- 

 lized, and in which silica is the first predominating ingredient. 

 Granite forms the base on which all others rest. To granite 

 succeeds gneiss, which is only a granite beginning to be slaty. 

 By degrees, mica predominates. Slates of different kinds appear; 

 but in proportion as the purity of the precipitations is changed'. 



