Flints of the Upper or White Chalk. 197 



been no signs of the specific contractility pertaining to 

 colloidal silicic acid ; the resulting siliceous mineral, instead 

 of appearing, when not rendered cherty by insoluble matter, 

 as * a colloidal glassy hyalite, would have presented itself 

 either as compact quartz, or possibly as an alkaline silicate ; 

 and, lastly, there would have been wanting the evidence of 

 the greater portion of the siliceous material having been, as it 

 were, continuously waylaid and absorbed, as it descended 

 from the surface of the ocean, into the colloidal protoplasmic 

 mass resting upon the immediate upper surface of the calca- 

 reous deposit. 



" In conclusion, I beg to express a hope that, although the 

 lengtli already attained by the present communication has 

 debarred me from bringing forwaixl a number of important 

 facts and observations which would have materially strength- 

 ened my ai'guments, considering the complex nature of the 

 inquiry and the special difficulties belonging to it, the follow- 

 ing conclusions have, on the whole, been fairly sustained : — 

 1. That the silica of the flints is derived mainly from the 

 sponge-beds and sponge-fields which exist in immense pro- 

 fusion over the areas occupied by the Globigerine or calcareous 

 ' ooze/ 2. Tliat the deep-sea sponges, with their environ- 

 ment of protoplasmic matter, constitute by far the most 

 important and essential factors in the production and stratifi- 

 cation of the flints. 3. That, whereas nearly the whole of 

 the carbonate of lime, derived partly from Foraminifera and 

 other organisms that have lived and died at the bottom, and 

 partly from such as have subsided to the bottom only after 

 death, goes to build up the calcareous stratum, nearly the 

 whole of the silica, whether derived from the deep-sea sponges 

 or from surface Protozoa, goes to form the flints. 4. That 

 the sponges are the only really important contributors to the 

 flint-formation that live and die at the sea-bed. 5. That the 

 flints are just as much an organic product as the Chalk itself. 

 6. That the stratification of the flint is the immediate result 

 of all sessile Protozoan life being confined to the superficial 

 layer of the muddy deposits. 7. That the substance which 

 received the name of ^Bathybius,^ and was declared to be an 

 independent living Moneron, is, in reality, sponge-protoplasm. 

 8. That no valid lithological distinction exists between the 

 Chalk and the calcareous mud of the Atlantic ; and pro tanto, 

 therefore, the calcareous mud may be, and in all probability 

 is, ' a continuation of the Chalk formation.' " 



The history of Bathybius is too well known to the scientific 

 world to need resuscitation in this place. Suffice it, therefore, to 

 say that Sir VVyville Thomson and Dr. Carpenter found what 



