219 



The known a!)ilities of the author, his zeal in this hranch of 

 science, and his careful discrimination in examining the charac- 

 ter of every natural product that comes under his observation, 

 are too well known to geologists to render it necessary for us to 

 say any thing in commendation of the work. We shall only say, 

 in one word, that it will not disappoint those practical geologists 

 who apply to it for information or assistance. 



To each of these families is prefixed a geological account of its 

 connexions, and of its position in the order of nature, together 

 with a sketch of its prevailing mineral characters and composi- 

 tion. This is followed by a detailed synopsis of every variety 

 which has come under the author's notice ; all of them being 

 minutely described in such a manner as to enable a student to . 

 ascertain any specimen by a reference to the table. 



In a number of preliminary chapters there are given many 

 matters essential to the general history and knowledge of rocks ; 

 and, among others, there are some appropriated to the purpose 

 of enabling the student to discover the place and name of a rock 

 from the nature of its component minerals. There is also a de- 

 tailed account of the reasons for adopting a geological in prefe- 

 rence to a mineralogical classification, which appear to us satis- 

 factory. We shall take an opportunity in a future number of 

 extracting some article for the purpose of giving our readers a 

 specimen of the design and execution of this work. 



Lately published. 

 Remarks on a Communication |)ublishcd in the xxth Number 

 of the Jounsil of Literature, Science and the Arts, entitled " Ob- 

 servations on the Chemical Part of the Evidence given on the late 

 Trial of the Action brought bv .Messrs. Severn, King and Co. 



E e 2 against 



