Some Recent Observations on the Brighton Cliff-Formation
Authors: Martin Edward Alfred 
Published: October 2009

The Author records in his paper certain features presented by the face of the cliffs between successive falls at Black Rock, Brighton, during the past eighteen years. As the cliffs have worn back, the base-platform of Chalk grows in height, and the layer of sand which Prestwich found above the Chalk grew thinner and thinner until finally it completely disappeared. At the same time, the raised beach has grown in thickness from 1½ to 12 feet. In 1890 there were 6 feet of sand, with a foot and a half of beach above it. There was practically no protection at this date in the shape of groynes. In 1892 the sand had decreased to between 3 and 4 feet, but the beach remained as in 1890. Many falls of cliff took place between 1892 and 1895, and at the latter date the beach had increased to between 4 and 5 feet. The eastern limit of the beds had become more clearly defined, the trough in the Chalk in which they had been defined taking an upward direction about 300 yards east of the Abergavenny Inn. Many blocks of red sandstone had become dislodged, and were lying on the modern beach. In 1897, 10 feet of chalk formed the lower portion of the cliff, with 8 feet of raised beach above it in places, but there was a mere trace of sand left. The rubble-drift above was seen to be distinctly stratified. ~any masses of red sandstone had fallen out of the cliff, the largest measuring 5 feet in its greatest dimension. In 1899, the raised beach had reached a thickness of 10 feet. Great masses of moved and reconstructed chalk were observed on the eastern boundary embedded in the beach. Two rounded lumps of granite were extracted from the beach. In 1903, the beach was but a little over 8 feet thick in the exposed parts, but the platform of Chalk was 14 feet thick. The upper portions of the beach, which were the least consolidated, had fallen away in such a manner as to leave cave-like gaps beneath the rubble. The number of red sandstone blocks which lay on the modern beach was remarkable, forty such blocks being counted in a space of 50 yards square. In 1906, the raised beach had increased from 15 to 20 feet : farther west, however, the thickness was not so great. In 1908, there were 17 feet of Chalk, 12 feet of beach. It is noteworthy that, as the degradation of the cliff proceeds, the material is rapidly carried away by the sea. No talus remains for any length of time, and if the material is to be prevented from disappearing into deep water, some such contrivance as chain-cable groynes seems to be demanded, fixed somewhere between low and high tide-marLs. The only organic remains observed in the cliffs were some fragments of shells, found at the top of the raised beach.

The President (Prof.
SOLLAS
) remarked that many years ago Mr. Jesson, F.G.S., had found plant-remains in the Elephant Bed at the base of the cliffs east of Brighton. These had been shown to Prestwich and Carruthers, but, owing to their imperfection, had not been determined. Perhaps the Author would state whether he had met with any specimens of better preserved plants.

The Author replied in the negative, and at the same time expressed his thanks for the reception accorded to his paper.