82 GEOLOGICAL MEMOIRS. 



8. It appears to result from this review of the phaenomena, either 

 that in the great depths beneath the surface there are ancient de- 

 posits, perhaps of coal, formed under conditions remarkably similar 

 to those now existing ; or else, which is more probable, that these 

 immeasurably great masses of tuff, pumice, trass and mud, erupted 

 from volcanoes, have been sucked in by the volcano from time to time, 

 in the form of existing turf and bog, or fen- mud, greatly assisted 

 perhaps by the vicinity of freshwater lakes and pools of water; and 

 then having been partially fused are thrown out again during the 

 next eruption. 



9. The invisible portion of the animal kingdom is thus found to 

 possess a new, important and unexpected influence upon the sohd, 

 and in this case volcanic portion of the earth, — an influence which 

 invites a closer investigation, and recommends itself to universal 

 attention. 



On the 24th of April 1845, Professor Ehrenberg made another 

 communication to the Academy, stating the result of further inves- 

 tigations into the subject, partly M'ith reference to some additional 

 specimens from Hochsimmer, and partly on various volcanic tuffs, 

 &c. from distant localities. 



I. On the Volcanic Infusorial Jiw^(PyROBiOLiTE) of the Rhine, 



Owing to the active researches of the local authorities, and espe- 

 cially of M. von Dechen, the author has obtained much new informa- 

 tion with regard to the Laacher-See and Hochsimmer ; and he states 

 that, including a firestone forwarded by M. Noggerath, not less than 

 thirty-nine difi^erent kinds of rock had been forwarded to him for 

 investigation. The geological relations of these rocks he considers 

 it highly essential to record ; and they are the more important, since 

 other objects had been forwarded to him for examination from distant 

 localities, and a comparison of the results with what we know of the 

 volcanic relations of the inland Rhine district would tend to a com- 

 pletion or rapid extension of our general knowledge of the subject. 



The sections at Hochsimmer are obtained from six points ; and 

 the following account is quoted by the author from a communica- 

 tion he had received from M. von Dechen : — 



" The first result is, that the peculiar infusorial mass is not con- 

 fined to the one stratum first made known, although the others re- 

 cently laid bare do not equal that in' purity and regularity. 



" From the relations of the originally exposed infusorial stratum, 

 the immediate deposit of the whole series of volcanic tuffs and con- 

 glomerates containing that bed, and resting upon the grauwacke, is 

 distinctly seen. 



" The thickness of the conglomerate and tuff, as far as it has been 

 hitherto proved, amounts to about 27^ fathoms or 165 feet ; and it 

 is not likely that the whole thickness is much greater than this, 

 since the grauwacke comes out to the day at no great distance to- 

 wards the north-east. 



