THE PHOSPHATE DEPOSITS OF FOLKESTONE 

 R, Gasey^ F.G.S . 



Phosphorus, an essential element of living 

 matter, is present in the earth* s crust mainly in 

 the form of calcium phosphate. It is a primary 

 constituent of apatite and some rarer minerals like 

 tTjrquoise and monazite. Deposits rich in phosphate, 

 known as phosphorite ^ are found in the sedimentary 

 rocks either as continuous sheets or in the form of 

 detached nodules or concretions. 



Small quantities of detrital monazite occur in 

 the East Cliff sands and in the Lenham Beds at 

 Paddlesworth; hut the principal sources of inorganic 

 phosphorus in the Folkestone area are the deposits 

 of nodular phosphorite in the Gault and Lov/er 

 Greensand formations. Both the Sandgate and 

 Folkestone divisions of the Lov/er Greensand have a 

 hasement hed rich in phosphorite- the junction of 

 the Lower Greensand and the Gault is marked hy an 

 important concentration of phosphorite nodules: 

 while in the Gault itself phosphorite is present in 

 numerous seams and in scattered nodules and frequently 

 forms the infilling matter of fossils. Nodules are 

 also found in the Hythe division of the Lower 

 Greensand and in the Lower Chalk. 



Great interest attaches to these heds of 

 phosphorite nodules since thnre is little douht that 

 they represent long periods of time and that they 

 were formed during intervals when the flow of 

 sediment to the sea-floor was greatly reduced or was 

 at a standstill. They are thus condensed deposits 

 which in other areas may he represented hy consider±»ls 

 thicknesses of strata. Commonly they are associated 

 with marine transgressions and with gaps in the 

 geological succession. Often these heds are highly 

 fossiliferous, for with suspension of normal 



