THE HISTOEY OP A DISCOVERY. 



41 



and of serpentine marbles of aU the varieties f urnislied 

 by our collections. These were examined with ordi- 

 nary and polarized lights and with every variety of 

 illumination. Dr. Hunt, on his part, undertook the 

 chemical investigation of the various associated 

 minerals. An extensive series of notes and camera 

 tracings were made of all the appearances observed ; 



Fig. 10. Group of Canals in the Supplemental Skeleton of Eozoon. 

 Taken from the specimen in wMch they were first recognised. Magnified. 



and of some of the more important structures beauti- 

 ful drawings were executed by the late Mr. H. S. 

 Smith, the then palseontological draughtsman of 

 the Survey. The result of the whole investigation 

 was a firm conviction that the structure was organic 

 and foraminiferal, and that it could be distinguished 

 from any merely mineral or crystalline forms occur- 

 ring in these or other limestones. 



