77 



Though not many of the Selsey erratics show glacial striae, 

 and the only agency of transport seems to have been ice-foot or 

 shore-ice, there is an astonishing mixture of far-transported 

 masses. In addition to the masses of Bognor rock just mentioned, 

 there are numerous greywethers or sarsen stones, pieces of 

 pudding stone, and masses of unmistakable Bembridge Limestone 

 from the Isle of Wight. These represent the Tertiary strata. 

 The Secondary formations are represented by numerous large 

 unworn flints, and by masses of Greensand chert, both probably 

 derived from the southern part of the Isle of Wight. But among 

 the more striking large erratics are masses of igneous and 

 metamorphic rock from the Channel Islands or coast of Brittany. 

 One small block of granite was evidently Cornish. 



So the English Channel was then as cold as the Atlantic round 

 the Isles of Scilly — cold enough for a thick shelf of ice to 

 accumulate along the shore every winter, and then to break away 

 and transport masses weighing a ton or more right across the 

 Channel- The ice must have been thick, in order to support such 

 blocks, and the water must have been so near the freezing point 

 as to allow the floes to drift hundreds of miles before they melted 

 away. 



A curious problem arises when we study the distribution of 

 the erratic blocks in the south of England, and its solution ought 

 to throw much light on the distribution of land and water during 

 the period of greatest cold. It will show that the apparent 

 digression we have been making is very much to the point, when 

 we study the ancient valleys of Bournemouth. 



Selsey shows an accumulation of erratics drifted from many 

 different places, and the same is the case with the scattered erratics 

 which are found all along the Sussex coast, and even here and 

 there on the coast of France. But as we pass westward into the 

 old estuary of the Solent these erratics disappear, till we have 

 only large blocks of greywether sandstone, such as can be seen in 

 abundance on the foreshore at Milford-on-Sea. 



This fact seems to imply that at the period when the erratics 

 were being carried, the mouth of the Solent River was not far 

 from Spithead. Outside Spithead drift-ice from the shores of the 

 English Channel brought erratics, and some of this ice probably 

 travelled with the tide a short distance up the estuary. Inside 

 Spithead, on the other hand, and everywhere higher up the old 

 river, only erratics brought down the stream by river-ice are found, 

 for all the Milford erratics may have come from the upper waters 

 of the present Frome or Avon. 



The occurrence of numerous large sarsen-stones at Milford 

 and Barton, unmixed with stones from the Isle of Wight or 

 Channel Islands, seems, therefore, to prove this point — it shows 

 that the chalk hills of the Isle of Wight were then still continuous 

 or almost continuous with those of E>orset, and that Bournemouth 

 was then on the bank of a river, not on the shore of the sea. 

 This gives us an approximate date for the breach in the hills on 



