228 



MINERALS AND GEOLOGY 



The annexed figures shew some of our more common or charac- 

 teristic forms : 



FIG. 128. 

 Graptolithus (Didyrnograptus) flexilis : Hall. 



FIG. 129. 



G. (Loganograptus) Logani : Hall. 



FIG. 130. 

 G. (Didyitiograptus) pennatulus : Hall. 



FIG. 131. 



G. ( Dicranograptus) ramosus : Hall. 



FIG. 132. 

 G. (Climacograptus) bicornis : Hall. 



FIG. 132.* 

 G. (Diplograptus) pristis . Hisinger. 



FIG. 133. 

 G. (PhyUograptus) typus: Hall. 



