360 MINERALOGY. 



Mineralogy of tator with Sublime emotions, not unaccompanied by 

 Shetland. fear. 



Set out for RoncCs Hill, the highest point of Shetland. 

 Walk over a granite country to Rona's-voe ; cross this 

 long and narrow roe, and land at the foot of precipices 

 of red granite, in which the hill terminates toward the 

 south and west. The hill is at first heathy, but toward 

 the top it becomes naked rock. Its top is a long ridge, 

 covered with fragments of decomposed granite. I at- 

 tempted to measure its altitude by a portable barometer. 

 I observed the barometer accurately when at the sea- 

 side, both before and after my ascent, and found it 

 stood exactly at the same height at each time, from 

 which I concluded that no material alteration in the 

 pressure of the atmosphere had taken plac<? during my 

 stay on the mountain. The barometer fell when on the 

 summit 15 tenths of an inch, but I had no thermometer, 

 which is necessary to perfect accuracy *". From Rona's 

 Hill, see to a vast distance around, — all the Mainland, 

 near seventy miles long, Foula, Fetlar, Yell, Unst, &c. 



Sail close to the promontory of Hillswickness, and 

 observe a great many reddish veins, traversing the mica- 

 ceous rocks which compose these awful cliffs. Some of 

 them were apparently several yards in diameter. 

 ' Pass at some distance a stupendous, insulated, and in- 

 accessible rock, called the Drongs. It appears some- 

 what like a vast ship under sail. It is of a red colour, 

 like some granite cliffs at a considerable distance on the 

 Mainland, the nearest rocks on shore being micaceous. 



Pass Isle of Doreholm, another insulated rock, per- 

 forated by a magnificent natural arch, through which the 

 distant shores of the Mainland were visible. The co- 

 lour of this is similar to that of the Drongs. Both are 

 probably either granite or wacken, similar to what Pro- 

 fessor Jameson describes as found in Papa Stour. A 

 sailor who had been the day before on the shores of the 

 Mainland nearest Doreholm, brought me fragments of 

 both granite and wacken, of a brick-red colour. 



~" * Supposing the temperature 50°, the height here indicated wa» 



about 1400 feet. 



Observe 



