The phosphatic "basement -"bed of the Sandgate 

 Beds is no longer visilDle in situ at Folkestone, 

 though loose hlocks from this "bed litter the shore 

 west of the old Victoria Pier. The base of the 

 Folkestone Beds is now similarly concealed, "but was 

 exposed during the construction of the promenade at 

 East Cliff in 1938. It consists of a "bed of sand, 

 about a foot thick, crowded with pebbles and 

 phosphatic material. At the bottom of the bed are 

 spherical concretions of brown sandy phosphorite 

 impregnated with iron. They occur up to six inches 

 in diameter and each is a little compendium of 

 fossil mollusca^ In the up'-er half of the bed are 

 numerous irregularly shaped lumps of black 

 phosphorite many of which are casts of ammonites 

 and other fossils. Some are phosphate encrustations 

 around bryozoan colonies. Phosphatized logs of 

 wood, teeth and bones of fishes and reptiles, are 

 found loose in the sand. That these nodules must 

 have lain for a long time unburled on the sea-floor 

 is shown by their coating of attached oysters 

 bryozoa and arnielids* This bed is of very local 

 occurrence and traced inland from Folkestone it 

 passes into norm.al uncondensed sediment. At 

 Brabourne it is replaced by about 110 feet of sandy 

 deposits, which emphasises its concentrated nature 

 and the long period of time necessary for its 

 formation. 



Of especial interest is the seam of phosphorite 

 at the top of the Foi.kectone Beds. This is the 

 Mammillatum Bed, so called because of the abundance 

 in it of the ammonite Douvilleiceras mammillatum . 

 This is one of the most widespread phosphate 

 horizons in Europe and marks an important phase of 

 inhibited deposition. It is distributed right across 

 south-east England, around the northern rim of the 

 Paris Basin and is found in the basin of the Rhone. 

 At Folkestone it appears high up in the cliff below 

 St. Peter's Church and above the East Cliff sandSo 



