Prqfensor Edicard Hull — Gravel Beds, Isle of Wig Jit, etc. 101 



In the Geological Survey Memoir by the late Mr. Bristow (second 

 edition, by Messrs. Clement Eeid and Aubrey Strahan, 1889) the 

 plateau gravels are again described very much as done by the previous 

 author, but necessarily more in detail. They are recognized by the 

 authors as of great antiquity, and that since their deposition they 

 have been traversed and broken into by the rivers on both sides of 

 the Solent. But the authors do not appear to have arrived at any 

 clear view regarding their origin and mode of formation, and in one 

 case vrhere the gravel is abruptly broken off at the edge of the ClifE 

 above Alum Bay, the attempt to account for it is appai'ently abandoned 

 as hopeless. I hope to be able to show that its position can be 

 clearly accounted for. 



Paet II. 



Terraces. — I may here be allowed to interpose a note regarding the 

 physical features vs^hich we call ' terraces ', or under the Prench form 

 we call ' plateaux '. There ai'e no more certain indications of changes 

 of level under various conditions than terraces, whether by the sea- 

 coast, the borders of lakes, or of rivers ; and wherever I have gone 

 I have studied their conditions with special interest. I have observed 

 their position and relative levels along the coast of the British Isles, 

 in England, Scotland, and Ireland ; along the borders of the 

 'Mediterranean, and the banks of the Nile, the Dead Sea, and the 

 River Jordan ; in all these countries they indicate the levelling 

 effects of the sea, the lake, or the river, at successive periods ; and . 

 they are evidence of former submergence. It is from such evidence 

 that we draw the inference that (as Mr. Codrington has correctly 

 inferred) the coast of Dorset and the Isle of Wight has been sub- 

 merged to a depth, of over 420 feet. But having regard to the 

 permanent level of the ocean Avaters, is it conceivable that this 

 submergence was confined within the limits of this area alone ? Why 

 should it not have extended in all directions as far as the hills and 

 uplands, rising into higher altitudes to the north, west, and east? 

 Por it cannot be questioned that the physical features of this region 

 had been determined before the period when the plateau gravel beds 

 were being accumulated. 



Isle of Wight : Evidence of an Ancient Sea-margin. — Some few 

 years ago, when on a visit to this island, with the aid of an aneroid 

 I spent my time in making observations of level, and, amongst other 

 places, I took the level of a gravel-bed at the summit of the cliff 

 overlooking Alum Bay, and also of the remarkable gravel terrace 

 south of Newport known as St. George's Down. My interest was 

 greatly aroused on discovering that the aneroid readings were very 

 nearly the same in both, cases — approximating to 400 feet above the 

 sea, or a little under. It then occurred to me that we had in these 

 readings evidence of the existence of an ancient sea-margin. On 

 ascending to the top of the St. George's gravel-pit, I found myself 

 on a nearly level terrace extending far westwards, and breaking 

 off in an abrupt cliff on the north and Avest sides. The beds were 

 found to consist mainly of rolled chalk-flints, rudely but distinctly 



