Notice of the Wonders of Geology. 3 



We have, in no degree, fallen off in our admiration of this 

 beautiful work.* In our remarks upon the first edition, we 

 stated our views of the different modes of treating geology, as 

 regards the order. That which Dr. Mantell has followed in 

 all the editions of the Wonders, is from the gravel down through 

 the alluvial and diluvial, the tertiary, the secondary and transi- 

 tion to the metamorphic and the primary rocks, the internal 

 fires and the volcanoes. This order has its advantages, but it 

 requires inconvenient anticipations. An individual who has tri- 

 ed, in courses of lectures, every order that can well be proposed, 

 has come to the conclusion, that the better mode is to begin 

 with the actual volcanic vents — the living fires of our world, con- 

 necting with them the dormant and extinct volcanoes — then to 

 descend with the evidences of regularly increasing heat in all the 

 rocks, until we reach the permanent internal fires — permanent 

 in as much as they are never entirely extinguished, although they 

 may fluctuate in position and intensity. 



In this manner we arrive, by an intelligible process, at the 

 region of the primary or unstratified rocks, now universally ad- 

 mitted to be of igneous origin, and thus we establish the domin- 

 ion of fire, all the doctrines connected with which are intelligible 

 and credible, and of commanding and pervading energy, among 

 the dynamics of the planet. We are also thus furnished with the 

 key to the intrusions of the igneous rocks among all the other 

 classes, and among each other, while the particular alterations 

 among the various classes of rocks, by the action of ignited and 

 melted masses, may be reserved for the time when those rocks 

 shall be in turn examined. 



From the granite, at which we thus arrive in our descent, we nat- 

 urally ascend in the chronological order of the strata, beginning with 

 the primary slates, as to whose alledged metamorphic character we 

 may thus be placed in a condition to form a judgment, since the 



* Prof. Silliman has had occasion during the late winter to make trial of its ca- 

 pabilities for the instruction of large popular audiences in a public institution. 

 The Lowell Institute at Boston, Mass., founded by the munificence of the late Mr. 

 John Lowell, a native and citizen of that place, who died at Bombay, while on hia 

 oriental travels, and left an ample endowment for the support of popular lectures, 

 as well as instruction in exact details on morals and religion, science, philosophy 

 and arts, &c. A geological course was given during the late season, to two audien- 

 ces, collectively amounting to three thousand people. While Bakewell and other 

 works were recommended to their perusal, the order of Dr. Mantell's Wonders was 

 followed in the lectures for the convenience of the audience. 



