6 BOROUGH OF LEWISHAM. 
conclude with the London Clay, which is the prevalent formation 
exposed at the surface. Inasmuch as there are in the less elevated 
localities tracts of ‘‘derived” London Clay generally containing 
sub-angular flints, it is well to explain that the clay, when 27 sztu, 
is quite free from such stones. True, it rests upon a basement 
bed consisting of a mixture of clay and wel/-rolled flint pebbles, but 
the mass of it is quite free from them. The large, rounded con- 
cretions frequently found in it are known as septarian nodules, 
because they sometimes contain internally sepa, or dividing bands 
of crystalline carbonate of lime. When opportunity offers it is 
worth while to break these septaria with a hammer, because they 
sometimes contain fossils. 
The London Clay being the uppermost of our local Tertiaries, 
it follows that the highest elevations are of that formation. As 
a whole it has been subjected to enormous denudation. At the top 
of the slope in Whitefoot Lane, leading up from Southend Village 
(which slope, by the way, is the east bank of the older Ravens- 
bourne), a good view may be obtained of Shooters Hill, rising 
to 42oft. and of the Crystal Palace, where the elevation is over 
3ooft. Both hills are of London Clay. The intermediate gap, 
about 7 miles wide, was undoubtedly also once occupied with 
London Clay rising to at least 5ooft. This has all been swept 
away. But the highest point at Shooters Hill does not by any 
means represent the original deposit, because there, also, denuda- 
tion has occurred. It is worth while to spend a few hours in 
exploring the summit of Shooters Hill. The observer will ask,, 
Why should this huge pyramid of clay have withstood the in- - 
fluences which occasioned the denudation all around? If he has 
used his eyes in approaching the summit by way of the main road 
from Blackheath he will have noticed in roadside banks and 
gardens near the summit numerous water-worn flints, some of 
large size. Then in a narrow alley between the fences of enclosed 
pleasure grounds, that on the west side appertaining to Severn- 
droog Castle, he will see a gravel pit, and through the fence may 
at times discern in the gravel white quartz pebbles. Returning 
to the main road proceed a short distance down the eastern side 
of the hill towards Welling, and take the first turning on the left. 
Examine the bank on the left side of that road. A few years ago 
we dug from it fragments of ferruginous sandstone. From the 
opposite side of the same road there is a newly-formed road. 
When it was in the making we saw there pebbles of jasper and 
quartzite, also numerous large water-worn, pitted flints with a 
specific gravity much exceeding that of ordinary flints. Further 
to the north there is an open piece of grass-land with shallow 
sand pits. The sand varies in colour, but some of it is highly 
ferruginous. Geologists are agreed in thinking that this puzzling 
drift on the top of Shooters Hill came from the former Wealden 
heights far away to the South, but they differ in regard to the 
period of transportation. In Mr. H. B. Woodward’s ‘‘Geology of 
