cxcviii Journal of Proceedings.
had been compelled by circumstances over which he had no control to
postpone the delivery of his paper. On the table he had placed Norden's
map of Essex (1594), which members might find it interesting to com-
pare with a modern map of Essex on nearly the same scale. Unfor-
tunately, topographical accuracy could not be expected from ancient
maps ; but on the ancient map was an island, which did not appear in
any shape on the corresponding part of the coast in the modern map,
and that seemed a point worth noting. On visiting Christchurch,
Hampshire, in 1880, he had seen that the mouth of the Avon had been
deflected about a mile and a half eastward of its position (as shown on
the Ordnance Map) by a bank of shingle which had come round
Hengistbury Head, in the course of a very few years, in consequence of
the workings for ironstone at that promontory. In Norfolk he had seen
shingle used for roads, but it made extremely bad ones, as it would not
bind. He quite agreed with Mr. Topley that it should be treated as a
national possession and placed under the care of some government
department.
Professor R. Meldola stated that he was glad of the present oppor-
tunity of personally expressing his thanks to his friend Mr. Topley, not
only for the interesting paper which he had communicated to them, but
also for the readiness with which he had responded to his (Professor
Meldola's) appeal for assistance on the present occasion. One point
which the author of the paper had brought out very distinctly was of
great importance to those commencing the study of geology, vit., the
fact that coast erosion was brought about mainly by atmospheric
agencies, and that the action of the sea itself was only of a secondary
character, its function being to remove the cliff materials and other
debris furnished by the weathering of the coast formations. The rate of
erosion of any coast thus depended primarily upon the nature of the
formations exposed, as was well exemplified by their own coast at
Walton-on-the-Naze, where, the materials being London Clay capped
with Crag, rapid erosion was going on. In 1880, in company with
Messrs. W. and H. Cole, he had had opportunities of visiting the locality
named, and was then much struck with the fact that the London Clay
was weathering away, chiefly along the lines of jointing, in the form of
cubical blocks, the disintegration being much assisted by the percolation
of water through the fissures and seams. The foreshore was strewn with
the debris of these clay blocks which had been worn away by the sea,
leaving only the harder nuclei in the form of " sepiaria," or what some-
times appeared to be masses of fossilised vegetation. The amount of
material that had crumbled away and had been removed by the sea was
shown also by the immense number of shells from the Crag formation
that were strewn along the shore and mixed up with the recent shells,
thus furnishing for future geologists a splendid illustration of " derived
fossils." Of other places where Professor Meldola had been able to see
the course of erosion due to the atmospheric disintegration of soft