y 



35 



accumulated by the action of seas and rivers during a long 

 period of time, uader various conditions of climate, and 

 with many changes iu the relative position of the land, I hope 

 to be able to explain the order of succession of those 

 changes, to give a brief description of their results, with 

 notices of the animals and plants that tenanted the lands 

 and waters during that ancient period ; and thus to illus- 

 trate the physical history of Ashford and its vicinity, with- 

 out inflicting on you any great amount of fatigue. A few 

 introductory remarks on the sequence of the rocks or strata 

 to be noticed will be found useful, and I beg you to bear 

 in mind that all these rocks were formed at the bottom of 

 the then existing seas. It is supposed that the rocky 

 materials which form the earth's crust are about ten miles 

 in thiokaess, and that granite appears to be the lowest ; 

 but it will suffice for our purpose to notice that there are 

 several kinds of rocks in the lower part, and that the 

 wealden reposes on the oolitic rocks, which are about the 

 middle set. Immediately above the wealden we find the 

 lower greensand, oq the top of which the gault appears ; 

 above the gault we have the upper greensand, and next the 

 chalk-marl ; and then the chalk of which our downs are 

 made ; above the chalk are the London clay and other 

 clays andsauds called the tertiaries. 



THE WEALDEN. 



"We shall commence our journey at Kingsnorth, which is on 

 the north-east boundary of the exposed portions of the geolo- 

 gical formation called the weald or wold, being the low 

 wooded country lying between the north downs and south 

 downs of Kent and Sussex. The wealden group of strata 

 is of fresh-water origin, and consists chiefly of clays and 

 shales, with subordinate beds of sands, sandstones, and 

 shelly limestones, the fossils in which indicate an estuary 

 or brackish- water origin. The wealden is supposed to occupy 

 the site of an ancient estuary, which received the clay and 

 mud of some gigantic river whoso waters occasionally bore 

 down the spoils of land plants and land animals, to be en- 

 tombed along with those of aquatic origin; andlbisformation 



