12 



A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 



(5) Then came ice with a stratified appearance, arising from the distribution of 

 bubbles in sheets. Bands, a couple of inches thick, carrying abundant bubbles alter- 

 nating with others carrying less bubbles. Here a vertical prismatic structure was 



W$$&8®$S 



llpis 



IFt. Hard Snow. 



3". Recrystallised Neve. 

 6". Coral loidal Ice. 



18*. Granular, crystalline 

 Ice loaded with bubbles 

 arranged irregularly. 



18. Stratified with 

 Pr is"m structure . 



5 ..6. Clear Prismatic Ice 

 with conchoidal fracture; 

 Coarser grained above, 

 finer below. 



2. coarse Prismatic Ice 

 with fragments of alga, etc. 



3. Clear, Prismatic Ice 

 with conchoidal fracture 

 and Strong radial flutmgs. 



I . Clear Prismatic ice 

 evidencing strain. 



/RocK Bottom with 

 •\fragments of alga,etc. 



Fig. 3. Blue Lake Section 



moderately well defined and, taken in conjunction with the arrangement of bubbles, 

 is evidence that that ice originated by the freezing of ponded waters. 



(6) At about eighteen inches from the top of the stratified bubble-ice the layers 

 became indistinct and the structure was gradually lost, at the same time the ice became 



