44 



of tlio Society for 1879. Ou the side of the valley opposite the 

 Chartham Lunatic Asylum, there is a hill conspicuously marked 

 by a clump of Scotch pines, not far from which is the parish school- 

 house, which may be reached by way of a very pleasant footpath 

 through I5i_i;berry Wood. It is near here in the western corner of 

 BIgberry Wood that some deep holes arc situated, with subter- 

 ranean streams that may be heard running at the bottom. I visited 

 two of them and measured their depths by means of a stone tiellto 

 the end of a ball of string. They are from twenty-five to twenty- 

 nine feet deep, and are very difficult to find on account of the thick 

 imderwood. A hole very similar to these suddenly opened at 

 Wingham in February, 1877, to which I drew attention at the 

 time. See report for 29th .January, 1878, page 29. The holes in 

 J3igbcrry Wood pass through the Thanet-sands for about twenty- 

 five feet to the chalk. The jS"icker Pits below Westbcre are in 

 peat and alluvium covering the Thanet-sands, so that some people 

 have supposed that they are caused by the former springs issuing at 

 a lower level. Both are probably only part of the much more ex- 

 tensive drainage of the uplands, and may so be related. The 

 opening at Wingham is in loam covering the chalk. The Nicker 

 Pits, which are not more than two hundred yards from the South 

 Estern Railway, are irregularly shaped openings usually filled with 

 water on a level with the spongy surface of the marsh, which 

 undulates as it is walked across, and owing to its very loose and 

 boggy nature renders it very difiicult to reach the edge of these 

 curious openings, the situation of which may be made out from the 

 railway by some stunted willows and osiers planted round their 

 margins. For further particulars respecting these peculiar wells, 

 sec an article, by Mr. John Brent, in the Geologist, 1860, vol. III., 

 page 276, who ascribes their names to the "Scandinavian god 

 Isikarr or Knickarr, in Christian times converted into old Nick, and 

 so Nicker pits or the devil's pits." As this is rather a description 

 of the physical goograpliy than the geology of this part of the 

 country, it will not be out of place hero to mention that swallow- 

 holes and blow-wells, as they are called in other counties, arc 

 accounted for by the chemical action of water containing carbonic 

 acid in solution, which, flowing over a bed of loam or clay over- 

 lying limestone rock, is by such an intervening stratum prevented 

 from acting on it, until by some accident it finds its way to the 

 chalk. It then, first by chemical action and afterwards by 

 mechanical, enlarges one of the natural fissures of the rock until a 

 swallow-hole is formed. The mechanical action of water will 

 sometimes drill a circular hole througli rock of the greatest hard- 

 ness, as may be seen under many water falls. It is very seldom 

 indeed that water runs through a hole without a whirling motion ; 

 take, for instance, the familiar example of water making its exit 

 from a sink. When this occurs on a larger scale in nature, stones 



