On the Agricultural Geology of England and Wales. 461 



rooted on the fluvio-marine deposit containing the mammalian 

 remains. The same fact is also attested by the "presence of the 

 remains of the rhinoceros and hyaena in Cefn Cave, in Denbigh- 

 shire, beneath sand containing the marine remains of the erratic 

 tertiaries which overspread the surrounding country. 



Peculiar characters of the erratic tertiaries. — There are pecu- 

 liarities in the composition of these marine deposits which dis- 

 tinguish them from other tertiary strata, and which, combined 

 with their present irregularity of distribution — an irregularity 

 rather apparent than real, and the result of denuding action — 

 caused them at one time to be referred to the transient action of 

 the sea bursting in enormous waves over the land. The charac- 

 ters which were deemed proofs of such transient action are the 

 slightly worn and scratched condition of the smaller detritus and 

 larger blocks; the rounded, polished, and striated condition in 

 some places of the rocks on which they rest — in others their 

 shattered state ; the masses of fragmentary matter enveloped in 

 these deposits, which must have been transported from various 

 distances, unabraded and unmixed with other matter ; the large 

 size of some of the far transported blocks or boulders ; the great 

 irregulea'ities of surface over which they must have travelled; 

 their transport from lower to higher levels ; the broken condition 

 of the shells ; their general absence from large areas and from a 

 great depth of deposits ; the confused intermixture of species in- 

 dicating different habits, and different zones of depth ; their arctic 

 character ; the arctic character of the associated mammals, not 

 even excepting the elephant and rhinoceros, which are proved by 

 the woolly covering of those carcases which have been preserved 

 with the flesh and integuments entire in the frozen cliffs of Siberia, 

 to have been capable of enduring the rigours of a northern climate. 

 These, and other phenomena, too numerous to be specified, 

 which are in perfect accordance with the atmospheric and marine 

 action of an arctic climate, as described by the polar navigators, 

 combine to render gradual submergence of the land, proceeding 

 from north to south, while an arctic climate was advancing south- 

 wards, and its gradual re-elevation to about its former level, during 

 the return of a milder climate, the most probable solution of the 

 complicated phenomena of the erratic tertiaries. 



We prefer the term erratic tertiaries to that of pleistocene, in 

 order to distinguish them from those probably contemporaneous 

 deposits of more southern regions which are destitute of the 

 erratic characters above described ; and though we believe those 

 characters to have resulted from the action of shore ice, and 

 floating icebergs, and of an arctic climate on sinking land, we 

 prefer the term erratic to that of glacial, as involving no theoretical 

 consideration, but merely expressing the fact of the presence of 



