THE PRESERVATION OP EOZOON. 125 



according to Giimbel, present the same connecting cylinders 

 and branching stems as the pargasite, and are by him supposed 

 to have been moulded in the same manner. . . . Yery 

 beautiful evidences of the same organic structure consisting 

 of the casts of tubuli and their ramifications, were also ob- 

 served by Giimbel in a purely crystalline limestone, enclosing 

 granules of chondrodite, hornblende, and garnet, from Boden 

 in Saxony. Other specimens of limestone, both with and 

 without serpentine and chondrodite, were examined with- 

 out exhibiting any traces of these peculiar forms ; and these 

 negative results are justly deemed by Giimbel as going to 

 prove that the structure of the others is really, like that of 

 Eozoon, the result of the intervention of organic forms. 

 Besides the minerals observed in the replacing substance of 

 Eozoon in Canada, viz., serpentine, pyroxene, and loganite, 

 Giimbel adds chondrodite, hornblende, scapolite, and probably 

 also pyrallolite, quartz, iolite, and dichroite." 



(D.) Glauconites. 



The following is from a paper by Dr. Hunt in the Bejport of 

 the Survey of Canada for 1866 : — 



^^ 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 

 deposits from water, filling cavities in minute fossils, or 

 forming grains in sedimentary rocks of various ages. Al- 

 though greenish in colour, and soft and earthy in texture, it 

 will be seen that the various glauconites differ widely in 

 composition. The variety best known, and commonly regarded 

 as the type of the glauconites, is that found in the green-sand of 

 Cretaceous age in !N"ew Jersey, and in theTertiary of Alabama; 

 the glauconite from the Lower Silurian rocks of the Upper 

 Mississippi is identical with it in composition. Analysis 

 shows these glauconites to be essentially hydrous silicates of 

 protoxyd of iron, with more or less alumina, and small but 



