Description of the Bare Hills. 353 



mass of the mineral, we discover occasional cavities or depressions, 

 filled vi^ith small dendritic formations, discolored, and sometimes, 

 rendered almost black, by manganese, and having the appearance of 

 minute shrubbery. 



Pursuing the same course, upon the margin of the trench or 

 ditch by the road side, at D, and distant ninety two yards from A, 

 and so onward to E one hundred and twenty six yards, we meet 

 with another striking example of " accessory minerals dissemina- 

 ted" in serpentine and constituting ophiolite. The rocks between 

 these two points, appear, on a close examination, to have been 

 perforated with innumerable holes of an acute rhombic form. At 

 the surface of the' rocks, I have never discovered any appear- 

 ance of the mineral that once occupied these holes. But on break- 

 ing the rock, and obtaining a fresh fracture, we observe numer- 

 ous crystals of the above form, enveloped in the mass, and from 

 I to y\ of an inch in width. It is this substance that has by ex- 

 posure, been decomposed, and has left the cavities open. What 

 it is, I have not been able, satisfactorily, to determine. The crys- 

 tals are often well defined, and of a pale greenish color; it resembles 

 in a degree, some of the varieties of actynolite and epidote. But 

 I am not aware that either of those minerals is so liable, on expo- 

 sure, to decomposition and total disappearance from its gangue. 



Proceeding south in the same line to F, two hundred and twenty 

 seven yards from the point of departure A, we discover in the rocks 

 upon the left hand, a vein of semi-opal, running in a S. E. direction. 

 This mineral is often found upon the surface, in various other places 

 in this district. But in no one have I found it so pure and trans- 

 parent as at this place. 



Ascending the hill still farther to G, distant two hundred and forty 

 yards from A, and near the point where the road-makers commenc- 

 ed excavating the rocks upon the side of the hill, we find a small 

 vein of very fine " quartz rezinite" or Pitch stone, inclining to the 

 N. E. This locality is the only one I believe, that has been dis- 

 covered, in this district. It is highly probable, however, that the 

 same mineral may be found at other points of the same formation. 

 The above vein has yielded, at different times, very fine specimens, 

 seldom however, of a greater thickness than ^ or | of an inch. 

 The mineral is enveloped in a greenish talc chlorite, and is, in its pres- ' 

 ent state, quite thin, and appears as if running out ; consequently 

 it is not easily found. It is more than probable, however, that by 



