376 Reviews — Life of Sir Joseph Prestwich. 



were given in an excellent descriptive memoir, combining a complete 

 account of the stratigraphy and paleeontology of the district. The 

 list of fossils, together with plates of new species, form an important 

 feature in this publication. Not only were the organic remains of 

 the several formations discriminated, but even the characteristic 

 forms of successive horizons were distinguished, and the bearing 

 of the palasontological evidence on the geological conditions of 

 deposit were luminously discussed. This Coalbrookdale monograph 

 must be regarded as one of the classics of English geology, making 

 a notable advance in the progress of stratigraphy, and serving as 

 a model for subsequent investigation of the geological structure of 

 our coalfields. It appeared before the then recently organized 

 Geological Survey had mapped any of those parts of the country, 

 and it is remarkable how closely the mapping of the Survey in 

 subsequent years followed the lines which he had laid down." 



" But, unquestionably, the most important of Sir Joseph's original 

 contributions to science are to be found in the series of papers which 

 he wrote on the older Tertiary formations of the South-East of 

 England, and on the younger deposits containing the earliest traces 

 of man. This brilliant work was begun, carried on, and completed 

 during the scanty intervals of leisure which he could snatch from 

 a busy mercantile life. Properly to understand its scope and value 

 we must go back to the earlier decades of this century, and take 

 note of the vague and confused ideas then entertained by geologists 

 as to the arrangement and strati graphical value of the series of 

 deposits that overlie the Chalk. The term London Clay had been 

 applied by William Smith to those deposits from the argillaceous 

 character of their chief member. Subsequently various geologists 

 noticed the occurrence of a group of sandy and clayey strata between 

 the main mass of the London Clay and the top of the Chalk. 

 These were grouped together as Plastic Clay and Sand, but their 

 true stratigraphical value and palceontological interest were hardly 

 recognized. In the year 1846 Prestwich published the first of 

 a long series of papers in which he gradually worked out the true 

 relations of the several members of the series, and brought them 

 into relation with their equivalents in France and Belgium. The 

 story of this evolution of clear order out of the confusion that had 

 preceded Prestwich's researches has been well told by Mr. Whitaker, 

 who lias followed so worthily in the footsteps of the pioneer whose 

 labours he chronicles.^ Beginning among the cliff sections of the 

 Isle of Wight, Prestwich traversed every part of the Hampshire 

 and London Basins, recording his observations on copies of the 

 Ordnance Maps and in voluminous notebooks. From j'ear to year 

 he communicated his results to the Geological Society, each paper 

 throwing new light on the history of the geological formations, 

 until in 1854: his great essay on the Woolwich and Reading Series 

 added the coping-stone to the edifice he had so patiently reared. 

 He showed that between the top of the Chalk and the base of the 

 London Clay a group of strata, which he had called the 'Lower 



1 " The Geology of London" : Mem. Geol. Surv., vol. i (1889), p. 88. 



