390 Henry Woodward and W. Davies — 



Tjest therefore to term the whole development the Triassic series, 

 ■without making any subdivisions (which would have no real value) 

 to correlate them with the divisions made on the Continent. 



The consideration of the red rocks in the south-west of England, 

 -with their many evidences of false-bedding and irregular accumu- 

 lation, has led me to be rather sceptical of the importance attached 

 "to the unconformities observed to the north ; but my knowledge of 

 that district being confined to the inspection of some isolated 

 sections in Cheshire and Nottinghamshire, I have naturally no 

 opinion to offer concerning them. 



Whilst the organic remains of the Permian period approach nearer 

 to those of the Carboniferous rocks than to the Trias,' it seems im- 

 portant to keep in mind their approximation in physical character to 

 the newer rocks ; and when we take into consideration the evidences 

 of unconformity that have been recognized in the Permian rocks 

 themselves, to consider whether they are not equally important with 

 those found locally to exist between the Permian and Bunter beds, 

 and those between the Bunter and Keuper. 



The absence of the Muschelkalk in the British area must not of 

 itself be taken as any evidence whatever of an unconformity, con- 

 sidering the different conditions under which the beds were deposited 

 in each area. 



Thus it will be seen that there is no very strong evidence for a 

 great break in the Triassic series throughout the British area, but 

 that locally in them, as in the Permian series, there were pauses in 

 deposition accompanied by some erosion of the beds. 



The results of further researches may be looked for with interest, 

 and more particularly in regard to the Permian beds. 



Lyell has remarked " that nowhere have geologists found more 

 difficulty in drawing a line of separation than between the Secondary 

 and Primary series,"^ and perhaps future researches may lead to the 

 resumption of the term '-'Poikilitic" as a general term to embrace 

 the Permian and Trias, especially as it has been used by such men 

 as De la Beche and John Phillips. 



II. — Notes on the Pleistocene Deposits yielding Mammalian 



Eemains in the Vicinity of Ixford, Essex. 



By Henry "Woodward, F.R.S., and William Davies, 



Of the British Museum. 



THE "Valley of the Thames, with its numerous tributaries, like 

 nearly all our English river-courses, contains more or less 

 extensive deposits of Brick-earth and gravel, which were accumu- 

 lated at a period long antecedent to that when the streams had cut 

 their higher channels down to the depth at which they at present 

 flow. 



' The Permian flora is, upon tlie whole, very nearly allied to that of the Coal- 

 measures, though the Permian species are mostly distinct, and there are some new- 

 genera. In the Trias are found some Palseozoic types, as Galamites. — Nicholson, 

 Manual of Palaeontology, pp. 494, 533. 



^ Student's Elements, 1871, p. 366. 



