ART. 2. 



PETROLOGY AT GOOSE CREEK SHANNON. 



Measurements of apophyllite, Figure 29. 



79 



Apophyllite is frequently observed resting on stilbite and laumon- 

 tite in such a manner as to show it to be later than both of these. 

 It is thus near the end of the series although earlier than calcite 

 which was several times seen coating apophyllite crystals. The 

 apophyllite associated with the axinite has been mentioned under 

 that mineral. It was frequently noted that apophyllite crystals 

 associated with the other zeolites were largely dissolved and removed, 

 mere friable skeletons of the crystals remaining. 



Calcite is not an abundant mineral at this locality, although it 

 was found at several places, but nowhere in great amount. It is 

 present in the lot of material from the east-west shear zone collection 

 from the north central part of the quarry face in October, 1922, as 

 numerous crystals up to 5 mm. in length associated with albite, 

 white hornblende, laumontite, etc. These crystals are brilliant, trans- 

 parent, pale amber colored rhombohedra. They appear to be later 

 than all of the other minerals in the specimens, even the laumontite. 

 The dominant form is the rhombohedron <;?• (2241) with or without 

 other smaller modifying faces, a typical crystal from this lot having 

 the habit shown in figure 31. This gave the following measurements: 



Measurements of calcite crystal, Figure 31. 



