82 
On the Phosphoric Strata of the Chalk Formation. 
But when this fossil bed dips into the sea (unless, indeed, as is 
suspected, it be a second and lower one, similar to some strata 
afterwards found in this geological position in the Isle of Wight), 
the proportion of phosphoric acid is much greater, being 25 '27 
per cent., or equal to 52 • 17 of the phosphate of lime. 
On the west of Folkstone the bed is seen opposite the church 
at the top of the cliff, with which it runs parallel, about 3 or 
4 feet below the surface, for a considerable distance towards 
Sandgate. The fossils here are in a matrix of loose loamy sand, 
and are in every respect similar to those found in the neighbour- 
hood of Farnham. 
In the Isle of Wight, from Culver Cliff to Atherfield Point, 
wherever a junction of the gault with the lower green-sand has 
been examined, the phosphoric fossil beds have been discovered. 
The fossils in character and composition are identical with those 
of Farnham, and therefore need no further description. Only 
one exception was noted, which occurred in the ravine at the top of 
Shanklin Chine, where all the fossils of the junction were almost 
wholly composed of the sulphuret of iron. 
On the beach at Shanklin, Luccomb, Ventnor, &c., very many 
tons of these fossils might be picked up at low-water for less 
expense than the cost of gathering the lumps of sulphuret of 
iron, which is understood to be five shillings per ton. Amongst 
the fossils there are large quantities of black fossil wood, frequently 
encrusted with a grey cement of phosphate of lime and sand. 
This wood is very rich in phosphoric acid. 
It is very probable that the fossil forest imbedded in the Weal- 
den clay at Brook Point is impregnated with phosphoric, instead of 
carbonic acid, as is generally assumed. In appearance the wood 
is similar to that which was analysed above. 
The strata of the lower green-sand below the junction beds 
have not yet been carefully investigated for the purpose of dis- 
covering phosphoric remains. A few cursory observations, how- 
ever, have been made. At Folkstone there are huge masses of 
rock lying upon the beach, which consist of a conglomerate of 
unusually large grains of green-sand thickly interspersed in a 
matrix of a greyish colour ; this rock, when broken up, contains, 
amongst other matters not estimated, a percentage of — 
Insoluble silicious matter . . . 30'60 
Phosphoric acid . . . . . 7 " 23 
Potash 3-31 
Soda ■ 1-02 
The large green grains are readily separable from the matrix 
acid could only have existed in combination with oxide of iron, the lime 
being united with sulphuric acid, and really being present as gypsum, 
since it was all dissolved out by water in the analysis. — [J. T. W.] 
