INTRODUCTION. 113 



Greenough's map were particularly good ; the geological 

 colouring embraced Smith's results, and was partially founded 

 upon his own observations. The original edition appeared in 

 six sheets; in 1826 a reduced map was published and at once 

 obtained a wide circulation. New and improved editions of 

 Greenough's map continue to appear at the present day, and 

 for a long time this map was the best that existed. 



Smith's example gave a new impulse to geological work. 

 John MacCulloch, 1 a physician in private practice, gave up his 

 practice and devoted himself between 1811 and 1821 to the 

 geological investigation of Scotland. The first fruits of his 

 important labours were published in 1819 in his Description 

 of the W.I. of Scotland. In 1826 he was commissioned by 

 the Minister of Finance to prepare a geological map of that 

 country. This large undertaking was completed in 1834. 

 There were, however, no detailed topographical maps of 

 Scotland available at that time, and MacCulloch had to enter 

 the geological colours on the meagre topographical basis of 

 the Arrowsmith map. MacCulloch's map was published 

 posthumously in 1840. It frequently passed under the name 

 of the author of the topographical map, and received on its 

 appearance little attention even from geologists. Nevertheless, 

 MacCulloch was one of the pioneers of British mineralogy and 

 geology. 



The country which he investigated was bristling with com- 

 plexities and difficulty of every kind, but a wide mineralogical 

 knowledge and experience stood him in good stead, and he 

 built up a thorough groundwork for the general features in the 

 distribution of the rock-varieties in Scotland. Although a 

 little unwillingly at first, owing to MacCulloch's personal 

 peculiarities and unpopularity, his memoirs have long been 

 recognised as classical works in the history of British geology. 

 They are characterised by accurate mineralogical determination 



1 John MacCullcch, born 1773 in the island of Guernsey, of Scotch 

 descent, was educated in Cornwall, and studied medicine in Edinburgh. 

 He became so enamoured of mineralogical studies that in 1811 he gave up 

 his practice, and in the same year he communicated to the Geological 

 Society several papers on the structure of the Channel Isles and Heligoland. 

 In 1814 he was appointed a geologist on the Trigonometrical Survey. He 

 belonged to no particular school ; he frequently fell into scientific disputes 

 with his contemporaries, and was very unpopular on account of his per- 

 emptory way and jealous temperament. He died in 1835, through a 

 carriage accident in Cornwall. 



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