View source for Excursion to St. Mary's Cray, Well Hill, and Shoreham, Kent. Saturday, June 26th, 1874 - Geologists' Association excursion

'''Director—Professor J. Prestwich, F.R.S. (report by Henry Walker, F.G.S.) (Proc. Vol. iv. 15. 155.)'''

On arriving at St. Mary's Cray, the party inspected the cutting at the Station, which exposes lower pebbly beds of the Woolwich -and Reading Series and Thanet Sands. The valley-deposits, close to the Gas Works, were then visited. These were found to consist of ten or twelve feet of fine loamy brick-earth, with land-shells, and a little gravel; the whole having a "rain-wash" aspect. The Chalk was seen below. Professor McKenny Hughes gave a lecture on the physical history of the landscape of which this valley is one of the features, and then a start was made for Skid Hill, where Prof. Prestwich was to meet the Members, and act as Conductor for the day. Walking from St., Mary's Cray, Kevington, East Hall, and Skid Hill, the last named signalised by two grand trees of Portugal laurel (''Cerasus Lusitanica''), were successively reached.

The physical and topographical features immediately westward were first explained, Keston, Knockholt Beeches, and the long dry valley of the upper Cray being notable objects in the view. Skid Hill itself (capped with gravel) is but a portion of the interesting outlier of Thanet Sands and Woolwich Clay which at Well Hill—a mile further along the same elevation--has a still larger capping of gravel, of great age and singular interest. At length the higher ground, more than 600 feet above Ordnance Datum, was reached, and the Well-Hill gravel sections confronted the visitors. Here, above the Thanet Sands and the Woolwich Beds, were large rolled flints, highly fossiliferous, in a reddish, unstratified sandy matrix. A closer search discovered fragments of chert and ragstone. These Prof. Prestwich referred to the Lower Greensand beds at the Sevenoaks Range, some six miles further south, and sedarated from Well Hill by the deep and broad vale of Holmesdale. The Well Hill gravel, according to Prestwich, is a solitary patch of marine gravel, of Glacial age, which once stretched over Kent, and is altogether an unique geological monument in the county. Before leaving the spot the following orchids were gathered on the damp parts of the heath about Well Hill — ''Orchis maculata'', ''Habenaria bifolia'', and ''Liostera ovata'', and close at hand under the trees ''Ophrys muscifera''.

The following objects, to which Prof. Prestwich called attention on the arrival at Shoreham may also be mentioned :—Some notable sand-pipes in the Chalk, by the side of the high road to Sevenoaks, between the eighteenth and nineteenth milestones; a very fossiliferous bed of Chalk with ''Inoceramus'', near the first shaft at the north entrance to Halstead Tunnel; and a dry upper valley of the Chalk (south branch of the Timberden valley) with six feet thickness or more of flints, the water standing at a level below the valley fully 100 feet deeper than it once stood. Lastly, the visitors viewed from the hill near Darent Holme, the trumpet-mouthed valley of the Darent, opening out into the Weald, but draining in the opposite direction into the Thames.
==References==
===Maps===
Ordnance Survey. Geological—Sheet 6. 8s. 6d. 

New Ordnance Survey—Sheet 271. 1s.
===Book===
Whitaker, Geol. London. 1889. 2 vols. 11s.