Excursion to Croydon, Shirley, and Addington. May 7th, 1881 - Geologists' Association excursion

From: A record of excursions made between 1860 and 1890. Edited by Thomas Vincent Holmes , F.G.S. and C. Davies Sherborn, F.G.S. London: Edward Stanford [For the Geologists’ Association], 1891. Source: Cornell University copy on the Internet Archive (Public domain work)

Figure 33 Perna Croydonensis, E. T. Newton, From Park Hill, Croydon.

Figure 34 General section from the Crystal Palace over Park Hill to Oxted.

Figure 35 Park Hill section on the Woodside and South Croydon Railway.

Directors: John Flower, M.A., F.G.S., J. Logan Lobley, F.G.S., and H. M. Klaassen, F.G.S. (Proc. Vol. vii. p. 145.)

The members of the Association left East Croydon Station, and proceeded eastward along the Upper Addiscombe Road, passing over the extreme western edge of the Oldhaven Beds, and a small outlier of London Clay, extending northward from Park Hill. The sands of the Oldhaven series were well seen in one or two excavations recently made in digging foundations for new houses.

Near the southern end of Ashburton Road the party examined, by the kind permission of the occupier of the land, Mr. H. Johnson, two remarkable springs in the side of the hill on the south side of the road—one at a point about thirty feet, and the other about forty feet above the level of the road. The former of these, which is by far the larger of the two, is about 255 feet above the sea level. It has hollowed out for itself a considerable basin in the hill-side, which has probably been increased artificially, and the stream flowing from it has cut out a considerable valley for itself. These features were here pointed out by Mr. Flower, who also explained the general structure of the hill, and of the Oldhaven and Woolwich and Reading Beds of which it was composed. He also stated that there were numerous similar springs along the northern side of this hill, forming some of the sources of the Wandle and the Ravensbourne. The general opinion is that these springs arise at points where Clay Beds, dipping to the north, come to the surface of the ground on the side of the hill, and there discharge the water absorbed by the large masses of overlying Pebble Beds,

The party then proceeding towards Shirley House, the course of the watershed-ridge, here very broad and flat, dividing the basin of the Wandle from that of the Ravensbourne, was described by Mr. Flower. He also pointed out a spot on the watershed-ridge, in a ditch, about forty yards from the Stroud Green Road, where; in winter, a spring rises, from which the water flows eastward into the Ravensbourne, and westward into the Wandle.

After inspecting another fine spring and a small lake the party proceeded to the Addington Hills, where the section of the lower beds of the Oldhaven series at the back of the Sand-Rock Hotel was inspected, and described by Mr. Lobley, as also a pit excavated in the upper beds of the Oldhaven series.

The Addington Hills form the northern escarpment of the Oldhaven and the Woolwich and Reading Beds; the former here attain a height of nearly 500 feet above the sea level. Attention was particularly called to the small valley immediately at the foot of the hills, cut down into the Chalk, and to the still larger valley between that and the South Norwood Hill, which is formed in the London Clay, the two valleys being, together, about four miles across. Mr. Flower suggested that probably this was once the valley of the ancient stream which came down the valley from Merstham; while the deep valleys which run up into these hills were caused, in times long past, by the action of springs similar to those already visited. The watershed between the Wandle and the Ravensbourne crosses these valleys nearly at right angles.

By the kind permission of the Archbishop of Canterbury Addington Park was next visited. A small lake fed by springs from the Pebble Beds, and situated in a deep valley cut out of them was examined and described by the Directors, and the party then moved on to the Pinetum, where were seen some very fine specimens of Abbies Douglasi, A. Menziesi, and Pinus nobilis. The "Fir Mount," overlooking Addington village, and the site of a hunting seat much used by King Henry VIII., was the last point of special interest in the Park. From here fine views were obtained, embracing the high grounds of Worms Heath, four miles distant: these are capped with Pebble Beds, no doubt once continuous with those in Addington Park.

Proceeding down -the steep face of the escarpment to Addington village, situated on the Chalk, the party returned home by the road on the southern side of the park. In the beautiful lane between Heathfield and Ballards. the Wandle and Ravensbourne watershed was again crossed. At the Ballards Farm two remarkable blocks of sandstone, believed to be Sarsen stones, and lying on the Chalk, were examined by permission of Mr. Chas. Goschen. From here the party returned, across the fields, to the East Croydon Station.

[There have since been two excursions to Croydon, the object of both of them being to inspect the Park Hill section on the new railway from South Croydon to Woodside. The first took place on July 1st, 1882, Mr. H. M. Klaassen being Director; the second on June 2nd, 1883, the Directors being Prof. John Morris and H. M. Klaassen. Full accounts of this section are given by Klaassen (Proc., vol. viii. pp. 226-248, and vol. xi. p. 464), to the first of which is added an Appendix by E. T. Newton, "Note on a New Species of Perna from the Woolwich Beds," and a " Note on Coryphodon Remains from the Woolwich Beds of the Park Hill Section, Croydon" (pp. 248-254). The following brief details are extracted from Mr. Klaassen's papers, to which the reader desiring fuller information is referred.]

From the Paper "On a Section of the Lower London Tertiaries at Park Hill, Croydon," by H. M. Klaassen, F.G.S. (Proc., vol. viii. p. 226.)

"Park Hill Section, on the Woodside and South Croydon Railway, extends from the Upper Addiscombe Road, Croydon, to the footpath bridge near Coombe Road. Its length is 3,593 feet, of which 1,254 feet are tunnelled, as shown on the diagram (Fig. 35) by the letters n—n; and there are three cuttings, the south, central, and north.

"In July, 1882, the Association examined the South Cutting. It was seen under most favourable circumstances : the weather had been dry for some time, the Mottled Clay stood firm at an angle of 45°, having been dressed to the same slope as the underlying sandy beds, and the neatly trimmed banks displayed the variously coloured strata with such admirable definition that the divisions in the section were seen at a glance. A rainy season has since greatly altered the appearance of this cutting, and its brilliancy only exists as a pleasant remembrance to those who have seen it.

"Before entering the cutting we observed, from the footpath bridge (at R., below S.S. W. in the section Figure 35), on our right, the Oldhaven outliers of Addington Hills and Croham Hurst, covered with heath, gorse, broom, and firs, and we noticed that the railway at Park Hill cuts through a ridge which, shaped by denudation, lies between the Chalk and the London Clay. The highest point at Park Hill is 282 feet; its well-marked Tertiary escarpment overlooks, with a southward face, the dip-slope of the Chalk, which attains a height of 797 feet at Woldingham; and at Sydenham, three miles north of Park Hill, the London Clay is 367 feet above the sea level."

From the footpath bridge we passed into the railway cutting and examined the Thanet Beds, the lowest strata exposed, and, as the section (Figure 35) shows, traversed higher and higher beds during our northward progress. The thickness of all these beds is given below.

Vertical Section of the Lower London Tertiaries at Park Hill.

		Greatest thickness feet
Brown and grey laminated Clayey Sand		10
Grey Sand		24
Pebble-bed		15
Hard white Shell-bed		10
Blue Clay with lignites		10
Mottled Clay		21
Lavender-coloured sandy Pebble-bed	1 ft 6 in
Green Sand (Bottom Bed)	3 ft 0 in
Greenish-brown Sand (Bottom Bed)	6 ft 8 in
Grey Sand (Bottom Bed)	2 ft 0 in
Brown Clayey Sand (Bottom Bed)	2 ft 0 in	15 ft 2 in
Thanet-beds		38 ft 0 in