1826.] Dr. Daubeny on Vokanos, 217 



prised in the works of Sir G. Mackenzie and others on Iceland ; 

 of the accounts handed down to us with respect to those volcanic 

 eruptions, that have taken place in Greece and the Archipelago ; 

 and of the remarks on those of the Canaries and other islands 

 off the African Coast, which have been communicated by Hum- 

 boldt, Von Buch, and other foreign geologists. 



Traces of the same agency are shown to exist in Asia Minor, 

 Palestine, Syria, and other countries of the East, and a line of 

 volcanic operations is traced from Kamschatka to Japan, and 

 thence, in an almost uninterrupted succession, to Java, >^umatra, 

 and the Andaman Islands. 



A few of the volcanos distributed over the Great Pacific, and 

 the Gulph of Mexico, are afterwards noticed ; and the whole 

 concludes, by bringing together the results of Humboldt's inves- 

 tigations on the continent of America. 



From this statement of the contents of the first three lectures, 

 it will be evident, that we cannot pretend to present to our 

 readers a complete analysis of the work; all we can undertake 

 to do, will be to give an idea of the manner in which the subject 

 is handled, by selecting certain portions for abridgment ; and we 

 shall begin by noticing the author's description of the volcanos 

 that occur in the neighbourhood of the Rhine. 



These are divided, according to his usual system, into post- 

 diluvial and ante-diluvial : by which terms, however, nothing 

 more is intended, than an expression of the fact, that the erup- 

 tions took place, after or before the period at which the valleys 

 were excavated. 



The volcanos of the Eyfel district, which intervenes between 

 the Rhine and the frontier of the Netherlands, furnishes us with 

 an instance of volcanos formed subsequently to that epoch. 



" Scattered over the greater part of the district alluded to, are 

 a number of small conical eminences, often inclosing craters, 

 the declivities of which are usually sunk much below the present 

 level, and have thereby, in many cases, received the drainage of 

 the surrounding country, thus forming a series of lakes, known 

 by the name of Maars, which are remarkably distinguished from 

 those elsewhere seen, by their circular form, and by the absence 

 of any apparent outlet for their waters. The sides of these 

 craters seem to be made up, of alternating strata of volcanic sand 

 and scoriform lava, dipping away in all directions from the centre, 

 at a considerable angle, and the same kind of material has in 

 many instances so accumulated round the cones, as to objiterate 

 in great measure the hollow between them, and to raise the level 

 of the country nearly up to the brim of the craters." 



The author proceeds to a detailed description of certain of 

 these craters, and of the accompanying streams of lava, in which, 

 however, we have not room to follow him ; and concludes, as he 



