THE CLIFFS AND THEIR STORY 



295 



\\his]ierings of the waves as they wash 

 against the great rocks at the base of the 

 cliffs, not a sonnd is to he lieard. It is as 

 if Nature herself paiil silent homage to 

 these majestic monuments of the dead 

 past. Suddenly the solemn hush is broken 



To do this, we must call in the aid of the 

 microscope, so that we may examine the 

 minute structure of the cliffs. If we make 

 a very, very thin section, or slice, of a 

 piece of this chalk broken away from the 

 cliff, and phxre it unfler the microscope. 



"A NARROW BAY THAT FACES THE NEEDLES.' 



by peals of uncanny laughter and shrill 

 calls from the ledges on the vertical face 

 of the cliffs. It is the laughter of the 

 nesting gulls, disturbed at our approach. 

 i\umbers swoop and circle over our heads, 

 tittering their shrill, plaintive cries. A 

 narrow bay that faces the Needles affords 

 delightful facilities to study our subject. 

 The shore is practically composed of 

 shingles, and on all sides there is ample 

 evidence of the action of the waves upon 

 the base of the cliffs, which helps us to 

 realise how the Needles have become 

 separated from the island by the combined 

 action of the atmosphere and the waves. 

 Should there have been a recent fall of 

 drbris from the face of the cliff we shall 

 probably be al)le to collect from amongst 

 the freshly-exposed masses some of the 

 fossils peculiar to the chalk formation. 



Now let us see if we can find out of 

 what materials the chalk cliffs are com- 

 posed, and how they came to be formed. 



we shall see that it is very largely com- 

 posed of countless minute bodies, more or 

 less symmetrical in shape, each built up 

 of a nimiber of globular chambers, arranged 

 in a scries. Scattered amongst these pre- 

 vailing globular bodies are other minute 

 shells, some resembling tiny replicas of 

 the beautiful Nautilus shells to be seen 

 in our natural history museums, to- 

 gether with sponge-spicules, etc. ; and 

 all are embedded in a fine white dust com- 

 posed of carbonate of lime. 



For many years the chalk cliffs were a 

 bone of contention and a great puzzle 

 amongst geologists, who were engaged in 

 striving to piece together the evidence 

 which should show how this \-ast area of 

 chalk had been formed in the past. One 

 great question was how to reconcile the 

 fact that chalk is almost identical in its 

 chemical composition witli ordinary lime- 

 stone, with the conllicting fact that it is 

 of an al)solutelv distinct internal struc- 



