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that the fine particles composing the slaty rocks are arranged length- 

 wise in the direction of the cleavage planes, and he attributes- bends in 

 the cleavage in its passage from one bed to another, to beds of different 

 lithological character offering different degrees of resistance to pres- 

 sure. The idea that cleavage may be due to crystalline action, he alto- 

 gether repudiates. The two last of the series, published in 1852 and 

 1854, describe respectively the cleaved and foliated rocks of Scotland 

 and Mont Blanc, and are chiefly devoted to the development of his 

 theory of the great " cylinders " or arches, in which he asserted that 

 the laminae of cleaved and foliated rocks lie. In these memoirs he 

 made no advance beyond his previous ideas, for he attributed the 

 formation of cleavage and foliation to the same cause ; and though 

 he indicated the fact, he gave no explanation of the reason of the 

 occurrence of planes of cleavage and foliation in arched lines, a 

 subject that has since in part been acutely treated of by Mr. Sorby, 

 and of which the full explanation seems not far distant. 



Besides these memoirs, Mr. Sharpe contributed to the Geological 

 Society various papers on special subjects : " On the Quartz Rock 

 of MacCulloch's Map of Scotland;" "On the Southern Borders of 

 the Highlands of Scotland ;" and various palaeontological communi- 

 cations : " On the genus Trematis ; " " On Tylostoma, a new genus of 

 Gasteropods from the Cretaceous beds of Portugal ; " "On the genus 

 Nerineea ;" and a note on the fossils of the Boulonnais, appended to 

 a paper by Mr. Austen on that district. He also furnished several 

 parts of a Monograph to the splendid publications of the Palseonto- 

 graphical Society, " On the Fossil Remains of the Mollusca found in 

 the Chalk formation of England," and on this important work he 

 was still engaged when he met with the unhappy accident that caused 

 his untimely death. 



Such is a brief outline of some of the scientific labours of Daniel 

 Sharpe a man, whose mind alike powerful and active, and well 

 cultivated, urged him successfully to grasp and make his own a 

 wider range of subjects than many geologists dare to attempt. 

 Neither should it be forgotten that all the while he was unceasingly 

 engaged in mercantile pursuits, and it was only during brief intervals 

 of leisure, when more imperative labours were over, that he accom- 

 plished what many would consider sufficient work for their lives. 

 And it is not in geology alone that he is known and appreciated : 



