EHRENBERG ON INFUSORIA IN IGNEOUS ROCKS. 75 



like and glassy semi-opal was not formed immediately by volcanic 

 agency. 



Two other cases in which microscopic animalcules were associated 

 with volcanic rocks had also been noticed by the author, but in 

 these the conditions were less distinctly marked than in the former. 

 One of them had reference to the red firestone of the north of Ire- 

 land, which has apparently undergone fusion, and in which some of 

 the chalk infusoria are distinctly present ; and the other was the 

 edible earth of the Tungasians, from the Marekan mountains near 

 Okhotsk, of which M. Ermann, jun., had brought specimens. So 

 long ago as in March 1843*, the author had stated that in this 

 edible earth, which appears under the microscope to consist almost 

 entirely of pounded pumice, there were three distinct species of 

 known siliceous Infusoriaf and one of Phytolitharia J. M. Ermann 

 considered, from the circumstances under which it occurs, that the 

 edible earth consists of a very fine, dry and meagre dust of pounded 

 rock, in which this strange association of infusorial animalcules has 

 unaccountably become mingled ; and the author admitted such an 

 explanation, describing the species as offering a remarkable instance 

 of geographical extension, whatever be the relation in which they 

 stand to the rock or formation. The recent investigations with re- 

 gard to pumice give a new interest to this remarkable fact, and take 

 away from its apparently anomalous character by showing that there 

 is no necessary relation of the organic remains in question to the rock 

 or deposit called Marecanite. With regard to the other instance 

 mentioned, that of the fused firestone, it appeared to possess little 

 general interest, since the rock containing the remains might easily 

 have become associated with the lava in which it was found, frag- 

 ments of the adjacent rock existing in it in considerable number. 



The only example of any distinct relation of microscopic organic 

 bodies with recent volcanic phsenomena was one recorded by M. von 

 Humboldt, and occurring near Quito, where an extensive volcanic 

 mud-eruption distinctly presents the phaenomenon of minute organic 

 bodies, especially those of vegetable origin, proceeding from the in- 

 terior of a volcano, apparently from a great depth and in direct as- 

 sociation with those volcanic effects which have upheaved mountain 

 masses. 



It has however lately become an important object of investigation 

 to learn where we are to seek for the first traces of organic lii'e, and 

 although for some time calcareous rocks have alone been considered 

 as affording distinct evidence of its existence, on account of tlic 

 cfiange effected in the siliceous parts of infusorial animalcules in 

 fused rocks, the anticipations of the author that these remains were 

 more permanent than liad been supposed, are fully borne out by the 

 facts about to be recorded, since he is now able to announce that 

 pumice both in its normal state and in powder, volcanic tuff, vol- 

 canic conglomerate, trass, decomposed porphyry and porcelain earth 



* Monatsbcricht, p. 104. 



f Fragilaria amp /deep halUf Gaillonella distans, and Tabellaria vulgaris, 



X Pilus plantce, 



h2 



