PLIOCENE STRATA. 411 



was able to bring forward a detailed account of his 

 studies in the form of a memoir on the Coralline Crag 

 [65], followed by another two months later on the Red 

 Crag [66], and by a third in the year 1870 on the 

 Norwich Crag [69]. These three memoirs were de- 

 layed in publication, and did not appear until the year 

 1871, when they were issued in successive numbers of 

 the twenty-seventh volume of the ' Quarterly Journal of 

 the Geological Society.' Though the observations re- 

 corded in them by Prestwich were the results of his 

 own sedulous examination of the ground, and though 

 the conclusions he arrived at were founded on his own 

 original researches, these papers made their appearance 

 after much time and labour had been spent in the in- 

 vestigation of the same deposits by other observers. 

 He was perhaps hardly aware to what extent his 

 earlier work had been forestalled in date of publication 

 by the labours of his younger contemporaries. As 

 original contributions to geology, his East Anglian 

 papers have thus not the same originality and fresh- 

 ness that were shown in his series of Eocene memoirs, 

 where he had the ground largely to himself, and 

 published his researches while they were still new and 

 not anticipated by other fellow-labourers. 



To one of his investigations in later Tertiary geology 

 reference may here be made as an instance of his 

 sagacity of observation. He had long been acquainted 

 with certain ferruginous sands scattered over the 

 North Downs from Folkestone to Dorking. He re- 

 cognised these materials to be different from the red 

 flint -drift or loam, on the one hand, and from the 

 outliers of older Tertiary sands and pebble - beds 

 on the other. In 1854 some highly ferruginous 

 parts of these deposits yielded a number of casts of 



