584 



and Lyme Regis, an inquiry which in the hands of Conybeare and 

 De la Beche gave us the Plesiosaurus, that singular " link between 

 Ichthyosaurus and Crocodile." (Geol. Trans. 1823, 1 ser. v.) 



Love of scenery and ill-health induced him to prolonged residence 

 abroad, and in 1819 and subsequent years we find him mapping 

 and sounding the lake of Geneva in 1823, tracing the geology of 

 the north coast of France, examining the fossil plants of the Col de 

 Balme in 1824, 1825, exploring the geology of Jamaica, where 

 lay his paternal estates in 1828 and 1830, reporting on the geology 

 of Nice and the Gulf of La Spezia. 



In the midst of all his pleasant labour, De la Beche found time to 

 prepare selections from the valuable memoirs in the Ann. des Mines 

 (1824) ; 'A Tabular View of the Classification of Rocks' (1827) ; 

 'Geological Notes' (1830); 'Sections and Views of Geological 

 Phenomena ' (1830) ; 'A Geological Manual ' (1831) ; ' Researches 

 in Theoretical Geology ' (1834) ; ' How to Observe ' (1835) ; ' The 

 Geological Observer' (1851). He officiated as Secretary of the 

 Geological Society (1831), as Foreign Secretary from 1835 to 1846, 

 and as President, 1848 and 1849. He was appointed Corresponding 

 Member of the Academy of Sciences in 1853. 



But the most important results of the labours of this eminent 

 observer are contained in those valuable Geological Maps of the 

 British Isles, which have been prepared partly by his hands, but 

 entirely by his direction. 



That which had been vainly solicited by the interests of agricul- 

 ture in 1805, was conceded to the urgency of geology in 1832 : the 

 ' Ordnance Geological Survey' was begun, with De la Beche for its 

 head or rather only officer, in the mining districts of Devon and 

 Cornwall. From this epoch began a new era of British Geology, 

 characterized by a minuteness of field surveying previously unknown, 

 by exact measurements of the thickness and inclination of strata, 

 by published maps and sections of unequalled truth and beauty. 

 De la Beche's maps of the great western district, one of the most 

 difficult tracts in Britain for the geological surveyor, appeared 

 with a valuable explanatory report in 1839. In the map which 

 accompanies the volume, the older strata of North and South Devon 

 are called ' Grauwacke.' Their true relation to the old red sand- 

 stone groups, suggested by Lonsdale, Murchison, and Sedgwick, 



