220 GEOLOGICAL FACTS OBSERVED 



A 



The Society will no doubt recollect the fact which I de- 

 scribed, of the under-surfaces of many of the beds of Trap in 

 Iceland, bearing unequivocal marks of their having been in a 

 state of fusion, of which there are various specimens in our ca- 

 binet. On finding the red tuffa separating the beds in Faroe, 

 I expected to meet with some indications of heat in that coun- 

 try also ; and I was not disappointed, though their occur- 

 rence was not so frequent in Faroe as in Iceland. Near 

 Kirkeboe, we observed a considerable degree of roughness 

 on the bottom of a bed of rock, which resembled some 

 that occurred in Akkrefell in Iceland so much, that the 

 specimens differ only in a shade of colour. At Kirkeboe, 

 such marks of fusion were in many places quite apparent ; 

 but I did not succeed in my attempts to procure a mass 

 of a size sufficient to exhibit, in a satisfactory manner, the ger 

 neral feature which is so remarkable. The most perfect I 

 could procure on a small scale, of that slagginess which was so 

 conspicuous in Iceland, was found on the hill of Leinum in 

 Stromoe. I had to regret that heavy rain, and the risk incur- 

 red in wandering among high precipices, while surrounded 

 by thick fog, prevented my exploring this mountain so com- 

 pletely as I wished. 



But whatever degree of doubt might have been left on my 

 mind by the appearances just described, it was entirely 

 dissipated by a new and most important fact, in rela- 

 tion to heat having operated in the formation of trap, 

 which first presented itself to our notice in the island of 

 Naalsoe, where almost every circumstance of importance 

 in the geology of Faroe is to be seen, and where the great- 

 est variety of the individual minerals which occur in trap 

 are to be found. This island lies opposite to Thorshavn, 

 being separated from Stromoe by a channel about five miles 

 broad. It consists of one mountain, rising to an elevation of ■ 



1500 



* 



