270 Notices of Memoirs— Mr. J. E. BMes Address. 



come to our assistance. The surface was probably a marsh-land, all 

 the evidence pointing to that conclusion, on which trees may or may 

 not have grown, — hut not necessarily a forest. 



I would therefore draw attention to the fact, that portions of the 

 land-surface, marked by the rootlets, have frequently been called the 

 "Forest-bed." Prof. Prestwich considers the rootlets as evidence of 

 the Porest-bed at Kessingland. Mr. Gunn, on an excursion of this 

 Society on one occasion to Gorton, alluded to the " Porest-bed " 

 peeping out at the base of that cliff; which deposit, however, was 

 this same Rootlet-bed 



After these more or less marine, estuarine and freshwater deposits 

 became land, there was apparently a pause for some little time. Then 

 came about the grand subsidence of the whole beneath the sea (as 

 proved by the marine shells in the middle part of the Pure Valley 

 Beds at Punton, overlying the Rootlet-bed, such as Leda myalis and 

 Ilya truncafa, both with their valves united, etc. Also by the marine 

 and estuarine shells — which have been sometimes erroneously called 

 Grag — that overlie the rootlet-bed at Bacton, etc., etc.). Thus was 

 apparently ushered in the P)rift or Glacial period. During the earliest 

 part of this subsidence, the Rootlet-bed (as might reasonably be 

 imagined) was more or less denuded, together with the Chillesford 

 Glay immediately underlying it ; then, all the gravels, clays, loams and 

 sands, forming the greater part of the cliifs and land of Norfolk and 

 Suffolk, were piled up more than 150 feet in thickness in places over 

 this old marshy land-surface, flattening and compressing the wood and 

 other vegetable matter that were first scattered over it.^ Eventually 

 these deposits were upheaved, and the present configuration of the 

 country brought about, with the assistance of subaerial agencies. 

 But the remarkable fact relating to this upheaval is, that the old 

 marshy land-surface, though more or less squeezed and twisted about, 

 was brought up, for the most part, apparently to about the same level 

 with respect to the sea, as it probably occupied when the vegetable 

 matter grew on its surface. 



As mentioned, with possibly a few trifling exceptions, all the 

 mammalian remains are to be found buried beneath the more or less 

 denuded surface of the Rootlet-bed and the Chillesford Clay. The 

 formations, underlying this marked line of unconformity, being the 

 " Rootlet-bed," with its associated freshwater-beds, the " Chillesford 

 Clay," and the " Norwich Crag " ; and in all these formations, 

 mammalian remains with drifted wood are to be found. 



Much unnecessary complication and confusion in the classification 

 and nomenclature of these Pliocene or Pre-glacial beds, which occur 

 around the Norfolk and Suffolk coast, has been caused by the term 

 "Porest-bed Series," as introduced in the year 1870 by Mr. Gimn,^ 

 and to its assumed stratigraphical position. It is stated by him to 

 consist of a triple subdivision, viz. "the Rootlet-bed," "Porest-bed," 

 and "Soil of the Porest-bed"; which sequence of deposits, however, 



' Eecently at East Dereham— situated in the middle of Norfolk — Glacial Drift 

 deposits, 120 feet in thickness, have been proved by a well-boring to overlie the 

 Chalk ; the pre-giacial beds being absent. See Proc. Norwich Geol. Soc. vol. i. 

 page 127. * Quart. Journ. Geol. Soc. vol. iivi. p. 553. 



