APPENDIX 299 



chapter which every geologist deserving the name 

 should study with care. 



I give here some of the more important facts 

 referred to by Hunt, and may add that subsequent 

 microscopic studies have familiarized me with the 

 occurrence of serpentine and other hydrous silicates 

 as fillings of the cavities of fossils of various geo- 

 logical ages, insomuch that I have come to regard 

 the occurrence of these rocks in association with 

 fossiliferous limestones as among the best available 

 means to enable us to ascertain the minute struc- 

 tures of shells, Foraminifera, corals, etc. 



The following remarks and analyses further illus- 

 trate Hunt's views on the relations of these minerals, 

 with some of the facts on which they are based : — 



" In connection with the Eozoon it is interesting 

 to examine more carefully into the nature of the 

 matters which have been called glauconite or green- 

 sand. These names have been given to substances 

 of unlike composition, which, however, occur under 

 similar conditions, and appear to be chemical de- 

 posits from water, filling cavities in minute fossils, 

 or forming grains in sedimentary rocks of various 

 ages. Although greenish in colour, and soft and 

 earthy in texture, it will be seen that the various 



