File:The Quarterly journal of the Geological Society of London (12684314643).jpg

1852.. DE LA CONDAMINE REVERSED FAULT AT LEWISHAM. 193
other parts of England, I have thought their occurrence in this
district worthy of remark, and as heing likely to elicit the attention
of other observers of our tertiary beds.
In conclusion, I have to draw attention to the discovery of two
extinct molluscs (Helix ruderata and H. incarnata ?, see fig. 4) in
the Copford marls, — a fact of considerable importance in estimating
the relative age of this deposit ; and I would observe, that not the least
interesting phsenomenon of the Copford freshwater beds is the super-
position of an upper member of the local boulder-formation (bed
No. 1) on the shell-marl, which latter, with its subjacent clays, rests
on an earlier member of this formation, — conditions clearly pointing
out the age of the intercalated deposit. This seems to accord also
with an analogous geological phsenomenon in the cliffs of Eastern
Norfolk and in other localities, as noticed in Sir C. Lyell's * Manual
of Elementary Geology,' p. 127.
2. On a Reversed Fault at Lewisham.
By the Rev. H. M. De la Condamine, A.M., F.G.S.
A RECENT section on the northern slope of Loam-pit Hill exhibits
distinctly a small "reversed" fault in the lower tertiary strata; and
the comparative rarity of this phsenomenon appears to render it de-
sirable that its existence in this locality should be noticed*.
Fig. 1 . — Section at Loam Pit Hill, showing the Reversed Fault.
Scale, 6 feet=l inch.
N.N.w.
S.S.E.
1, London Clay. 2. Pebble Bed. 3. Striped Sand.
The accompanying section (fig. 1) will show its precise character.
The average angle of fracture is 30° : the displacement 6 inches. Its

• See an instance recorded by Messrs. Prestwich and Morris, Quart. Journ.