SKETCH OF JOSEPH PRESTWICH. 255 



researches lie paid special attention to the lithological changes of the 

 strata and to the fossils. In consideration of this earlier work he 

 was awarded the Wollaston medal by the Geological Society. 



Having acquired some familiarity with the geology of France 

 by his former residence as a student and his frequent business there, 

 Mr. Prestwich, in the course of the studies which resulted in the 

 rearrangement of the Tertiary formations, carried his explorations 

 across the Channel to the corresponding formations of France and 

 Belgium, for the purpose of determining the correlation of the strata. 

 In the course of these investigations, at the suggestion of Dr. Hugh 

 Falconer, and in company with Sir John Evans, he examined the 

 valley gravels containing flint implements works of man associ- 

 ated with the remains of extinct animals, the discovery of which in 

 the valley of the Somme had been announced by M. Boucher de 

 Perthes without attracting special attention. The finds made here 

 could be compared with the somewhat similar discoveries made in 

 England in Kent's Cavern by McEnery and in Brixham Cave in 

 1858. All these evidences of man's antiquity, together with others 

 subsequently found in England, were studied by Prestwich and Sir 

 John Evans, with the result of fully establishing the contemporane- 

 ous existence of man with other Pleistocene mammals. The ques- 

 tion of the duration of man's existence upon the earth thus became 

 a subject of lively discussion, which still continues. The theory 

 of man's extreme antiquity, as indicated by these remains, which 

 Mr. Prestwich was inclined to embrace at the time, and which he 

 was among the first to promulgate in England afterward, underwent 

 a process of modification in his mind, and he was disposed in his later 

 works to reduce considerably the estimates he made then. In recog- 

 nition of his work as one of the pioneers in establishing the geological 

 antiquity of man, the Koyal Society in 1865 awarded him the Koyal 

 medal. 



As Dr. Prestwich grew older he paid more and more attention 

 to economic geology, and finally became one of the most eminent 

 authorities in that branch. His earlier studies on Coalbrookdale 

 and the Tertiary strata seem, in the light of after developments, to 

 have been preparatory, though unconsciously so, for such a career. 

 A lecture on the geology of Clapham The Ground Beneath Us 

 delivered about forty years ago to a local society, and his publication 

 on the water-bearing strata of the country around London, were in 

 that direction. The former work " has stood the tests of time re- 

 markably well," and the latter, first published in 1851, has become 

 a standard, and has lately been reissued with appendices. He was 

 engaged upon the Royal Commission on Metropolitan Water Supply 

 and upon the Royal Coal Commission, to the reports of which he 



