9* PHILOSOPHICAL TRANSACTIONS. [aNNO 1786. 



Through this tract of land there are many drains of water, which may be sup 

 plied partly from the falling of the rains in wet seasons, and partly from the 

 springs issuing from the hills ; and there is reason to suppose, that in a loose soil 

 these drains form channels in a course of time. At the place where the ground 

 has sunk before, and is now sinking, there is a drain from the marie under the 

 sand ; and I am of opinion, that the course of the water is in the same direction 

 as the valley between the hill and the sinking of the ground. That the sinking 

 of the ground is caused by the foundation being undermined, and I think by 

 water, is evident from the appearance of the ground in the valley. The soil is 

 full of fissures, and resembles an arch, which is sunk down, and has left two 

 abutments standing. As the hill more than counter-balances the pressure of the 

 sinking ground on the stratum of wet marie, the consequence is, that the rocks 

 at some yards distance, being only thinly covered with sand, are forced upwards, 

 and become visible, and the wet marie in many places is squeezed through the 

 sand with them. This appears to be the true reason of the sinking of the ground 

 at one place, and the rising of the rocks at another. 



That Mr. Sackette's account of the sinking of the ground at Folkstone is 

 founded in error, I have not the least doubt, from the present appearance of some 

 of the objects he describes. I am rather at a loss to follow him exactly, as the 

 oldest man in the town of Folkstone, I am told, never heard of the Mooring- 

 rock he mentions. I think by his description the sinking of the ground must 

 have been in his time at the same place it is now, as Tarlingham-house is not to 

 be seen on the other side of the town. Admitting this to be the case, there will 

 still be a difficulty respecting the relative situation of each place in explaining 

 what he calls a sketch of the country. 



If Mr. Sackette, in the description of his sketch of the country, had placed 

 each object according to its real situation ; and if the effects he has mentioned 

 had been real ones, they would have been truly wonderful, and worthy the 

 attention of the curious investigator of the hidden operations of nature ; but I 

 am apprehensive he had but very little better foundation for what he has said 

 than the vague and inconsistent reports of a few ancient fishermen. Tarling- 

 ham-house is by Mr. Sackette's account situated full as far beyond the hill as the 

 width of the plain ; but how deep the hill has sunk to render the house visible 

 over the top must depend on the situation of it, viz. how much higher it was 

 than the top of the hill. If the hill has sunk only 10 feet, there must have 

 been some external evidence of it, such as fissures round the base, and a very 

 steep ascent from the top of it, where the separation happened between it and 

 Tarlingham-house ; but there are no traces of any sinking of the hills. 



There is further proof that Mr. Sackette did not examine into the matte: 

 himself, but rested what he said on the report of others ; and this is, that Tar- 



