DURING THE TERTIARY PERIOD IN THE BRITISH ISLES. 23 



Outline of the Mineralogy of the Scottish Isles. Fresh from the teaching of Werner 

 at Freiberg, the future distinguished Professor of Natural History in the Edinburgh 

 University naturally saw everything in the peculiar Wernerian light. He gave the first 

 detailed enumeration of some of the eruptive rocks of the Hebrides, but of course 

 ridiculed the idea of their igneous origin. Having heard of a reported " crater of a 

 volcano " near Portree, he ironically expressed a hope that " probably there may be still 

 sufficient heat to revive the spirits of some forlorn fire-philosopher, as he wanders 

 through this cold, bleak country." 



The advent of Jameson to Edinburgh gave a fresh impetus to the warfare of the 

 Plutonists and Neptunists, for he brought to the ranks of the latter a mineralogical skill 

 such as none of their Scottish opponents could boast. The igneous origin of basalt, 

 which the Plutonists stoutly maintained, was as strongly denied by the other side. For 

 some years one of the most telling arguments against the followers of Hutton was 

 derived from the alleged occurrence of fossil shells in the basalt of the north coast of 

 Ireland. Kir wan, whose Essays appeared in 1799, quoted with evident satisfaction 

 Richardson's observation of " shells in the basalt of Ballycastle," and Eichardson him- 

 self, though the true explanation that the supposed basalt is only Lias shale altered by 

 basalt, had been given in 1802, by Playfair, in his Illustrations of the Huttonian 

 Theory, continued for ten years afterwards to reiterate his belief in the aqueous origin of 

 basalt. Thus the Tertiary volcanic rocks furnished effective weapons to the combatants 

 on both sides. The dispute regarding the black fossiliferous rocks of Portrush had the 

 effect of drawing special attention to the geology of the north of Ireland. Among the 

 more noted geologists who were led to examine them, particular reference must be made 

 to Conybeare and Buckland, who, in the year 1813, studied the interesting coast-sections 

 of Antrim. The report of their observations gives an excellent summary of the arguments 

 for the truly igneous origin of basalt, and a statement of opinion in favour of the view 

 that the bedded basalts are the products of submarine volcanoes. Berger also about 

 the same time described in fuller detail the geology of the Antrim district, and showed the 

 rocks of the basalt-plateau to be younger than the Chalk. He likewise made a study of the 

 basalt-dykes of the north of Ireland, and was the first to point out their prevalent north- 

 westerly direction. These memoirs, contained in the third volume of the Transactions of 

 the Geological Society, may justly be regarded, to quote the words of Portlock, as " the 

 first effectual step made in Irish geology." Portlock's own Report on Londonderry, 

 published in 1843, is still the most complete summary of information regarding the 

 geology of that interesting region. 



While such advances were being made in the knowledge of the structure of the 

 volcanic rocks of the north of Ireland, the geologist had already appeared who was the 

 first to attempt a systematic examination of the Western Islands, and whose published 

 descriptions are still the chief source of information regarding the geology of this 

 extensive region. Dr Macculloch seems to have made his first explorations among the 

 Hebrides some time previous to the year 1814, for in that year there were published, in 



