48 HAMPSTEAD HILL. 



It is stated that a fragment of a fossil shell was found in 

 a ferruginous concretion in the sands at Hampstead, but with 

 this exception there is no record of organic remains having 

 been found in these beds, and this is quite in accordance with 

 the unfossiliferous character of the sands of the same age in 

 other areas. By remains of organisms, therefore, the sands do 

 not afford evidence of the climatal conditions under which they 

 were deposited, though they themselves tell us something of 

 the geographical changes that were occurring in this part of 

 the world at the time of their deposition and immediately pre- 

 ceding it, but the fossils and position of clay and limestone 

 beds of similar age in England and abroad reveal to us a w^on- 

 derful story. 



Grains of sand are much larger and heavier individually 

 than the particles forming clay, and consequently sink to the 

 bottom of water in which both may be suspended earlier, 

 and therefore in the sea nearer to the shore than the very 

 minute clay particles. Hence these sands were deposited in 

 shallower water than the clay below, and, as they are in the same 

 area, it is evident that the sea bottom must have risen between 

 the clay period and the sand period, and that this elevation 

 of the sea bottom and consequent shallowing of the sea was 

 gradual is told by the upper beds of clay becoming more and 

 more sandy until the sands, pure and simple, are reached. 

 Thus we read and learn from the simple fact of the sands of 

 Hampstead being above the clay of Hampstead, the geo- 

 graphical changes that took place in this area long long 

 before history began to be written. 



The sands on the Heath have been excavated for a long 

 period for economical purposes, and consequently the old 

 natural level has not been preserved. An enormous amount 

 of sand has thus been artificially removed from the north-west 



