258 ISLA. MINERALS. 



that manganese has been found, but no one could point 

 out the place or produce a specimen, so that this remains 

 as yet a problem to be solved. The most remarkable 

 of the metals said to have been discovered here is 

 quicksilver, which was found in a peat moss on the 

 western face of the eastern ridge ; the quantity collected 

 having been two quarts by measure. This occurrence 

 took place upwards of forty years ago: none has ever 

 been observed since that period, nor has any conjec- 

 ture been formed of the source whence it was derived. 

 It is further said, that native sulphur has been seen in 

 the limestone ; but neither could I see specimens of this, 

 nor procure any satisfactory information respecting it. 

 The existence of cobalt and of emery, both described by 

 mere reporters of the questionable evidence of others, 

 seems more than doubtful. With respect to all these mi- 

 nerals it is proper to remark, that a general notion pervaded 

 the Highland proprietors, at a period well remembered 

 in Scotland, of the extent and value of their subterranean 

 treasures. Of the speculations suggested by persons, 

 often more interested in the research than in the dis- 

 covery, the mine of Strontian has been almost the 

 only one that has justified the views of the reporters. It 

 is not unlikely that the reports respecting the metallic 

 minerals of Isla, which are of the same date, owe their 

 -origin to views equally visionary, sometimes perhaps, 

 fraudulent. 



Some of the clay slate has been quarried for roofing, 

 but it is neither good nor very abundant. It affords 

 however large flags of great utility ; and similar slabs 

 of the quartz rock, adapted to the purposes of paving, 

 are raised for trifling uses in rural economy. 



It has been imagined that coal existed in Isla, and 

 some searches have been instituted in pursuit of it ; with- 

 out judgment, but possibly not without dishonest views, 

 since the excavations appear to have been made in quartz 

 rock and clay slate. There are no traces of secondary 

 strata throughout the island. 



