216 Analyses of Books, [SispT. 



obtained through the exertions of preceding observers, he 

 determined to take up the subject in a different point of view, 

 by examining the relations of these rocks to the products of 

 active or acknowledged volcanos, and with this design to begin 

 by making himself fully acquainted with the latter class of 

 formations. 



** For this purpose, however, a mere examination of hand 

 specimens was not sufficient, the spots themselves were to be 

 visited, and the circumstances of geological position, as well as 

 the nature of the rocks associated, carefully compared with what 

 was seen in the trap districts that had excited so much attention 

 and dispute." 



He therefore examined at different intervals the volcanic rocks 

 of France and Germany ; those of Hungary and Styria ; the 

 greater part of such as exist in Italy and the neighbouring 

 islands ; and the whole series of those which extend throughout 

 Sicily ; thus including in his examination most of the appear- 

 ances of the above kind that are manifest in this quarter of the 

 globe, except those in Iceland, already made known to us 

 through Sir G. Mackenzie and others ; in Greece and Turkey, 

 countries at present but little accessible ; and in the Spanish 

 Peninsula, where a few indications of igneous action have been 

 noticed as occurring. 



His observations in these countries constitute, in great mea- 

 sure, the contents of the two first lectures, for the author has 

 thought proper to retain this title, as indicating the sections or 

 chapters into which the work is divided, notwithstanding the 

 additional matter introduced since they were delivered, which 

 has swelled all of them to a length far exceeding the legitimate 

 limits of an oral discourse. 



We observe, however, with pleasure, an abstract of Beudant's 

 observations on the trachyte of Hungary, which, notwithstand- 

 ing their interest, have hitherto met with but little notice in this 

 country ; and likewise an account of the almost unexplored 

 volcanic district of Transylvania, communicated by Dr. Boue, a 

 ideologist well known from his papers on various parts of France 

 and Germany, and his Geognostical Essay on Scotland. 



The author's remarks on Auvergne have already appeared 

 under the form of letters addressed to Professor Jameson, and 

 a short account of the volcanos of Sicily, will be seen in the 

 sketch of the geology of that island, communicated originally to 

 the Bristol Philosophical and Literary Institution, and since 

 published in the Edinburgh Philosophical Journal. 



In other respects, the matter of the first two lectures may be 

 considered new ; but not so that of the third which is engrossed 

 by a large assemblage of facts, compiled from various sources 

 both ancient and modern, with regard to the volcanos that occur 

 in parts of the globe, which have not been visited by the author. 



Here we meet with a summary of the geological details com- 



