S4f GEOLOGICAL MEMOIRS. 



action. The application of the microscope to this subject, showing 

 that the condition of the siliceous infusorial cases is such as would 

 be the effect of exposure to very high temperatui'e, has fully con- 

 firmed this view. 



3. The stratified mass at Hochsimmer can no longer be considered 

 as an aqueous formation, fused into a mass by volcanic action imme- 

 diately after its deposit ; since the condition of the different strata 

 is not such as would be produced by such means. Several experi- 

 ments seem to prove that the most perfect fusion has been effected 

 in portions which are by no means the lowest in position. 



4. The tuff of Hochsimmer could not, it would seem, have been 

 formed under water, because the materials of the strata are not ar- 

 ranged according to the law of gravitation. The author states that 

 he has made out, by direct experiment, that the white, siliceous, in- 

 fusorial powder by no means retains its white colour, nor does it 

 arrange itself in the same way after being mixed under water with 

 the fine tufaceous ash with which it is interstratified. The hollow 

 cells also of these infusorial cases rise to the surface when mixed 

 with coarse particles, so that some other cause than mere deposit 

 from water must have produced the alternation of fine layers of these 

 with beds of coarse tuff. 



If it should be said that these coarser particles of tuff, amongst 

 the fine layers of infusorial animalcules, consist of concretions which 

 have formed in water from the more minute particles since the mass 

 was deposited, or that they have been formed at all by aqueous ac- 

 tion, the association with volcanic crystals, sometimes of consider- 

 able size, renders such an explanation impossible. In the same way 

 it seems impossible to account for the appearance by supposing that 

 the masses containing infusoria were deposited regularly in alterna- 

 tion with deposits of tuff, because the internal structure and compo- 

 sition of the tuff itself, and the fact that it is often partly and some- 

 times almost entirely made up of similar organic bodies, is directly 

 opposed to such a view. 



But again, it may be imagined that the infusorial animalcules were 

 introduced after the volcanic deposits had been effected, and partly 

 by aqueous action. To this idea, however, is opposed the fact of 

 their being almost always in fragmentary condition, and in great 

 part metamorphosed, — an appearance which the author has never 

 seen in the rapidly forming beds of these animal remains, either in 

 Berlin or in the Luneburg forest, or near Eger, however thick the 

 deposits may be. The regular stratification and distinctly arranged 

 appearance are also opposed to this view ; and indeed it becomes alto- 

 gether impossible, when we consider the mingling that there is of 

 Phytolitharia — the siliceous particles of certain minute vegetable 

 bodies — which could as little form and increase in these places, or 

 even penetrate to them, as the bones of quadrupeds. 



5. The Loss in the Rhine neighbourhood appears quite distinct 

 from the tuff, although it contains parts made up of organic bodies. 

 It bears no appearance of having undergone the action of heat. 



6. There are at this time ninety-four different species of micro- 



