244 Notice of Active and Extinct Volcanos. 



" Thus the whole number of craters in the Eyfel district, inclu- 

 ding those of the same date that are scattered along and near 

 the left bank of the Rhine within the limits marked out, appears 

 to be no less than thirty. 



" The sides of these craters, wherever their structure was 

 discernible, appeared to me to be made up of alternating strata 

 of volcanic sand and fragments of scoriform lava, dipping in all 

 directions away from the centre at a considerable angle, and the 

 same kind of material has in many instances so accumulated 

 round the" cones, as to obliterate in great measure the hollow be- 

 tween them, and to raise the level of the country nearly up to 

 the brim of the craters. 



" The formation of these cones seems likewise to have been 

 in some instances followed by an ejection of substances of a 

 pumiceous character, and the same kind of material, (whether 

 derived from these or from some antecedent eruptions, will be 

 afterwards considered,) is spread widely over the country bor- 

 dering on the Rhine, either in loose strata alternating with beds 

 of a loamy earth, derived probably from substances in a minute 

 state of division thrown out by the same volcano, and mixed up 

 into a paste with water ; or else forming masses of considerable 

 thickness, in which the fragments of pumice are intermixed 

 with the latter substance, and constitute together with it a cohe- 

 rent mass known by the name of Trass. 



" The volcanos of the Eyfel are also, as above noticed, ac- 

 companied by streams of lava, but these have not in my opinion, 

 like the generality of those seen elsewhere, been satisfactorily 

 traced to the craters, but seem rather to have flowed from the 

 sides or base of the mountains with which they are respectively 

 connected. 



" These Coulees, like the volcanic cones themselves, are 

 sometimes almost buried under heaps of matter subsequently 

 ejected, so that in the lava of Neidermennig, the quarry, from 

 whence the millstones are obtained, is worked at a depth of 

 eighty feet from the present surface. They are in some cases 

 analogous to the ejections of existing volcanos, but at others they 

 possess more of a basaltic character, being freer from cells than 

 true lavas generally are, although it can be demonstrated that 

 they too are (geologically speaking) of modern formation, inas- 

 much as they follow the inclination of the vallies, and must 

 therefore have flowed since the latter were excavated." 



In order justly to appreciate the full extent of evidence for 

 the volcanic character of the countries on the Rhine, it is ne- 

 cessary to go through with the details of description, which 

 are exhibited by Professor Daubeny, which at present it is 



