Dr. Mac Gulloch on the Vitrified Forts of Stotland. 257 



or accident. While one party asserted that a regular process had 

 -been carried on for the purpose of making- a solid wall, the other 

 supposed that these walls might have been originally constructed of 

 stone and wood united, and that accidental fire, or the attack of 

 an enemy, had destroyed the compound structure, producing in 

 consequence the vitrification now to be traced in them. Mr. 

 Williams and Mr. Fraser Tytler are the most conspicuous leaders 

 on each side. 



It seemed to me that light might be thrown on the question, by 

 examining with mineralogical accuracy the substances of which 

 these structures were composed, and noting the changes which 

 each had undergone from the operation of the fire, and also by 

 observing whence the stones had been derived which were used in 

 them ; and that the question of accident or design might be illus- 

 trated by examining in the laboratory the degree of heat necessary 

 to produce the requisite appearances in the stones which actually 

 exist in these structures. 



In the present more diffused state of mineralogical and geological 

 knowledge, it is unnecessary to refute the notion of their volcanic 

 origin in a paper addressed to a Society like this. For the pur- 

 pose of the ordinary spectator, that refutation may be trusted to 

 the increasing progress of natural knowledge. 



The hill of Dun Mac Sniochain, which lies in the plain, now 

 supposed by some to be the site of the ancient Beregonium, has 

 been long noticed as the seat of one of these extinguished volcanoes. 

 Having seen specimens of pumice and lava (as they were called) 

 collected from it, I was glad to have an opportunity of investigating 

 a very accessible specimen of what I concluded to be a vitrified fort. 

 Such it proved. 



The drawing, pi. 2. fig. 1, which accompanies this paper, contains 



Vol. II. 2 k 



