Mineralogy and Geology of a pan of Nova Scotia. 139 



Before alluding to these minerals, we would observe that 

 the compact trap forming the highest parts of this island is 

 rarely in masses which may strictly be called columnar, al- 

 though they have a tendency to that form, and in a few in- 

 stances, affect the pentagonal shape of basalt. We were 

 unable, however, to discover among them any appearance of 

 articulation in their columnar arrangement. It contains but 

 a small proportion of iron : and consequently the exposed 

 surfaces of the rock are very slightly altered by the oxyda- 

 tion of this metal, which in other places is more sensibly ob- 

 served. 



Of the many interesting minerals to be found at this place, 

 stilbite associated with calcareous spar is the most abund- 

 ant. This mineral, forming numerous veins in the amygda- 

 loid near the base of the precipice, presents, in the open in- 

 terstices of the rock, beautiful projecting masses composed 

 of long fasciculated crystals of a flesh red, and sometimes 

 straw yellow color. When crystalHzed, it is in elongated 

 rectangular four-sided prisms, terminated by tetrahedral py- 

 ramids. 



The calcareous spar is curiously scattered over the surfa- 

 ces of stilbite in acute rhomboids, which are often hemitro- 

 pic, deeply striated upon the faces of cleavage, parallel to 

 their horizontal diagonals, and of uncommon magnitude and 

 beauty. These crystals, usually colorless and transparent, 

 are in a few instances of a rich honey-yellow appearance. 

 In breaking the various masses which are scattered along 

 the shore, it is not unusual to meet with one, which, compo- 

 sed of yellow stilbite externally, contains, within, numerous 

 crystals of calcareous spar hning its walls in rhomboids, 

 which, having their faces deeply indented by the projecting 

 pyramids of the stilbite on which they are implanted, were 

 obviously deposited subsequently to the formation of that 

 mineral. 



Chabasie in rhombic crystals, transparent and colorless, 

 also of a beautiful orange yellow color, occurs at this place 

 in the fissures of the amygdaloid. The crystals present bril- 

 liant glassy faces, and are very large, frequently measuring 

 an inch across each rhombic plane. 



Agates of various kinds, jasper and chalcedony, also bo- 

 tryoidal cacholong, exist in the columnar rock above the 

 accessible base of the precipice : they may be picked up in 



