35 
greensand, chalk marl or grey chalk, lower chalk or chalk without 
flints, and upper chalk or chalk with flints. The chalk rested 
upon various formations according to locality, but in Sussex it was 
on the Wealden. Once it was uniformly spread over this, but 
the Wealden formation had been elevated, together with the chalk 
above it. The chalk had been severed by the anticlinal ridge of 
the Weald and separated into the North and South Downs, this 
fracture being evident from the fact that the North Downs have a 
steep face to the south and the South Downs a steep face to the 
north. The South Downs had rifts through which rivers flowed 
—probably originally fissures caused by unequal raising—but 
now widened and modified by the flow of the rivers. 
On the chalk was originally a considerable quantity of 
tertiary deposits, but these had mostly been removed by denuda- 
tion. Their remains existed in many places as a re-deposit— 
—such as the elephant bed between Brighton and Rottingdean, 
and the coombe rock and other beds near Portslade and 
Chichester. A few layers of the lowest series—-the so-called 
Woolwich beds—remain in situ at Newhaven Fort and Seaford 
Head. The chalk itself was mainly composed of small 
organisms which, dying, fell to the bottom of the sea—slowly 
forming a muddy deposit and enveloping the remains of fishes 
and other sea animals. There is, said Mr. Jenner, supposed to 
be a similar process going on in the Atlantic at the present time. 
The enormous amount of time necessary to form such an 
immense thickness of material as the chalk might be easily 
imagined, not only from the slowness of the accumulation of the 
material, but from the numerous changes in the forms of animal 
life which occurred from the base to the surface, changes 
which were remarkable and progressive. After an incidental 
reference to the presence of flints in the upper beds of chalk, to 
the large use of chalk for building purposes in medieval times 
and for lime in modern times, Mr. Jenner said the South Downs 
probably sloped gradually towards the south at the time the 
Channel did not exist and England joined France ; but the bases 
of the hills had now been cut off by the sea, and the white cliffs 
of Albion provided in Beachy Head and the Seven Sisters some 
of the finest scenery in the South of England. 
What the condition of the Downs was when the chalk first 
emerged from the sea was not known,—probably the elevation 
was gradual, and may have been in progress thousands of years. 
Of course, at first it was an absolutely sterile surface, gradually 
rounded by the action of water, which had given us the beautiful 
rounded contour. Then, probably, followed the lower crypto- 
gams and other first occupants of bare soils,—until we arrived at 
the present botanical conditions. He thought they might safely 
say that plants arrived before animals or man, and evidently 
there was some division in the direction of arrival, as some plants 
