100 Professor Edicard Hull— Gravel Beds, Ule of Wight, etc. 



II. — On the Inteeglacial Ge.vvel Beds of the Isr,K of Wight 

 AND South of England, and the Conditions of their 



FoRlfATION.' 



By Professor Edward Hull, M.A., LL.D., F.E.S. 



(WITH A FOLDING MAP, PLATE VI.) 



Part I : Introduction. 



Precious Author Hies. — The most importaut work dealing with my 

 subject is that by Mr. Thomas Codrington "On the Superficial 

 Deposits of the South of Hampshire and the Isle of Wight ".^ In 

 this elaborate essay, which includes all the area with which 

 I propose to deal, the author describes the gravel terraces on both 

 sides of the Solent, including the New Forest, showing how they were 

 originally distributed over surfaces gradually sloping downwards on 

 both sides towards the margin of the sea-coast from a height of about 

 420 feet on either hand. In the author's view, the plateau gravel 

 beds were spread as sheets over sloping surfaces, themselves 

 intersected by river-valleys which were widened and deepened at 

 a subsequent period after the deposition of the beds of gravel, so as 

 to leave abrupt faces and cliffs exposing sections of the strata. The 

 paper, which is illustrated by sections, leaves nothing to be desired 

 for completeness ; but in order to account for the deposition of the 

 gravel-beds he propounds a theory which I am unable to accept. 

 It is contained in clauses 3 and 4 of the Summary (p. 549), which 

 I here quote at length : — 



" 3. The spreading out of the gravel, and tlie levelling of the 

 tablelands, was probably effected in an inlet of the sea shut in on 

 the south side by land which connected the Isle of Wight with the 

 mainland, and opening to the eastward." 



"4. A gradual elevation appears to have gone on from the time 

 of the oldest and highest gravels down to the date of the low-level 

 gravel-beds, by which the inlet was narrowed into an estuary which 

 received the waters of all the rivers from Poole Harbour eastward ; the 

 Isle of Wight being still connected with the mainland." 



Prom the above quotations it will be seen that the author refers 

 the presence of the gravels to a very local origin, and assumes the 

 formation of a gulf by tlie uprising of a sort of barrier between the 

 extreme westerly end of the Isle of Wight and the mainland. But 

 I am unable to recognize the evidence of such an nprise of the strata. 

 The strike of the beds from the Needles to the Isle of Purbeck is 

 nearly E.-W. and seems to exclude the idea of a land connexion at 

 a time when, according to Mr. Codrington's own hypotliesis, thei'e 

 must have been a deep submergence amounting to over 420 feet. The 

 explanation I have to offer embraces a larger area of more general 

 conditions. At the same time I agree with the author I am quoting, 

 that the plateau gravels are of marine origin, deposited during a 

 gradual uprising of the land from a level of about 420-50 feet above 

 the present sea-surface. 



^ Communicated to the Geological Society of London, November 8, 1911. 

 - Quart. Journ. Geol. Soc, vol. xxvi, 528, 1870. 



