Thomas Pennant's A Tour in Scotland, 1769 (1771) and A Tour in Scotland, and Voyage to the Hebrides, MDCCLXXII (1774, 1776) played a key role, along with James Macpherson's Ossian poems of the 1760s, in representing the Highlands and Islands of Scotland as attractive places for a growing number of travellers and tourists. Brian D. Osborne claims in his introduction to a modern edition of A Tour in Scotland, 1769 that ‘to Pennant must go much of the credit for the non- Scottish world's discovery of Scotland and its development as a destination for travellers in search of the picturesque’. For Osborne, Pennant's appreciation of ‘the grandeur and natural beauty of Scotland’ made him ‘one of the first generation of travellers who saw in wild mountain scenes anything more than an awful wilderness’. Yet, as Charles W. J. Withers stresses in his introduction to a recent edition of A Tour in Scotland and Voyage to the Hebrides, 1772, although ‘Pennant was certainly aware of Scotland's visual grandeur, […] it is not a central theme of his Tour’. Pennant's central theme, I suggest, is the natural history of Scotland, and his tours helped to make the Highlands and Islands into primary destinations for travellers in search of the natural history of the northern wilds of Britain. Pennant attended to all aspects of Scotland's natural history, but in this chapter I focus on his geological observations, especially his discovery of impressive basaltic formations in the Inner Hebrides and what he took to be the remains of ancient volcanoes in various parts of Scotland – discoveries for which Pennant has not received any credit. I will also suggest, however, that there are significant interconnections between Pennant's observations of Scotland's geomorphology and his aesthetic response to its landscape.

Pennant was one of the foremost natural historians in eighteenth- century Britain. According to G. R. de Beer, he was ‘the leading British zoologist after [John] Ray and before [Charles] Darwin’.