476 QUATERNARY. 



part records only of particular physical conditions, chiefly Marine 

 or Estuarine, the Freshwater, and the more purely Terrestrial 

 deposits being less frequently preserved. Hence the study of these 

 newer deposits is in many respects more complex than that of the 

 earlier formations. 



In seeking a divisional line between Tertiary and Quaternary, 

 we enter, it is true, debateable ground ; for in the Eastern counties 

 there is a sequence of deposits from the Newer Pliocene (Forest 

 Bed Series) to the earliest Quaternary strata (Glacial Beds) ; and 

 many geologists object to the use of the term Quaternary as 

 unnecessary, for it suggests a great division among strata, which 

 neither in thickness nor in life-history can compare w^ith the 

 divisions of Primary and Secondary. Nevertheless, the term 

 Quaternary (introduced by A. Morlot in 1854) Ms largely adopted 

 in Europe and America; it is convenient to distinguish deposits 

 that on the whole were formed under different physical conditions 

 from the Tertiary strata, and that as a rule lie scattered with 

 marked unconformity over the denuded surfaces of the Tertiary 

 and older formations, from one end of the country to the other. 

 Moreover, the term Quaternary is convenient in marking the 

 period during which Man existed in this country, from that in 

 which no traces of his presence have been found.- The occurrence 

 of Man, indeed, renders this epoch of Geological history of especial 

 interest. 



In the early days of Geology the Quaternary deposits were 

 broadly divided into Diluvium and Alluvium. The former term is 

 now but little used, from the fact of its implying that the deposits 

 were mainly produced by extensive floods, and from the tendency 

 to associate them with the notion of a Universal Deluge.^ The 

 term Drift, used by Lyell in 1840 as a substitute for Diluvium, 

 is now applied generally to the Quaternary deposits, which consist 

 for the most part of gravel and sand, loam or brickearth, and clay : 

 it naturally refers to strata laid down at some distance from the 

 rocks, to whose destruction they are largely due ; but although 

 applied to River deposits, the word Drift is more appropriately used 

 in reference to the accumulations of the Glacial period. 



The occurrence of stones and boulders far removed from their 

 parent source early attracted the attention of geologists, but for a 

 long period the phenomena, now known as of Glacial origin, were 

 unexplained, and the Drifts were looked upon as little more than 

 "extraneous rubbish," the product of geological agents quite 

 distinct from those which helped to form the more ' solid ' rocks 

 that underlie them. Inasmuch as, in certain places, they rival in 

 thickness some earlier geological formations, and as taken 

 collectively, they have a more direct influence on Agriculture than 

 any other strata, their importance may readily be conceded. The 

 interest now taken in these superficial deposits was mainly aroused 



^ Bull. Soc. Vaudoise des Sc. Nat. iv. 41. 



* See Prestwich, G. Mag. 1870, p. 131. 



^ See Euckland, Reliquias Diluvianse ; H. H. Hovvorth, G. Mag. 1882, p. 266. 



