Studies in the Caleite Group. 241 



ical means. In making this table the soHd straight Hne on Fig. 4 

 was assumed to represent the correct progression of the molecular 

 volumes of dolomite with the variation in percentage of the 

 normal dolomite molecule. The specific gravity of dolomite 

 corresponding to the two end volumes was found to be 2.87 and 

 2.65. Interpolations between these end values give those recorded 

 for every 5 per cent, as shown in the table. In the same way, the 

 varying specific gravities for the other molecules were deter- 

 mined. If, for instance, the analysis showed 75 per cent of 

 CaMg(C03)o, the specific gravities of all the different molecules 

 corresponding to this particular molecular volume would be found 

 on the line of 75 per cent. 



