Oil the Phus2)lior{c Strata of the Chalk Formation. 75 
The fossils of this marl, tliough less numerous, are simihir to those at 
Farnliiim; exclusive of tliem the marl itself contains a percentage of 
Carbonate of lime .... 25*72 
Phosphate of lime . . . .14 -92 
Potash 2-69 
Soda -50 
The phosphoric green band is prolonged in the same S.W. course, fol- 
lowing the curve formed by the interior of the basin at the junction of 
the North and South Downs. The strata here, however, have not yet 
been minutely examined, nor have analyses beeu made in reference to the 
determination of the })resence of ])hosphatic matter : but a geological 
friend, writing in sillusion to this subject, says, " I observed, souie years 
ago, numerous fossils, fruits among others, in a bed of the genuine upper 
green-sand, exposed in a fresh-cut road leading from East Meon towards 
Peter.- field." 
In the Isle of Wight the phosphoric marl of the upper green-sand is 
extensively developed : it is found in enormous quantities at the back of 
the island, especially at the top of the Underclift', where it may be traced 
for several miles, Ivmg within a few feet of the surface. The thickness 
of the band varies from 3 to 7 and 8 feet; it is therefore easily attain- 
able. Organic remains abound, particularly am.monites and sponges ; 
the analyses of which, as also of the marl, are very similar to those of the 
Farnham beds. Here likewise the large spongoid bodies are very nu- 
merous, which are characterized by the usual ^peculiarities. 
Near Sutton Waldron, in Dorsetshire, the upper green-sand covers a 
wide expanse. Its junction with the soft diity-uhite marl above is well 
defined, but in other respects it differs from the correlative strata of 
Kent, Surrey, and Hampshire. In some places the marl degenerates 
into a pure sand, which is sufBciently arenacious to be used for making 
mortar. It contains comparatively but a very trifling Cjuantity of phos- 
phoric acid, whilst the chief constituent of its fossils, which are 
numerous in some parts, is carbonate of lime. In one field, however, 
some casts of small ammonites were found which contained a high per- 
centage of phosphates : the neighbourhood is, therefore, well worthy of 
a fuller investigation. 
At Mintern, on the contrary, both the marl and its fossils are of a 
richer character. A partial analysis of them gave, in a 
Speckled marl : — 
Silica (soluble and insoluble) . 
. 26' 
'68 
Phosphate of lime . 
. u- 
04 
Carbonate of lime . 
. 49' 
•23 
A green-sandstone : — 
Phosphate of lime . 
. 6' 
■07 
Carbonate of lime 
. 52- 
06 
Fossils in a brown marl : — 
Phosphate of lime . 
. 46 
•74 
Carbonate of lime . 
. 18 
•47 
In the marl : — 
Phosphate of lime . 
9 
•10 
Carbonate of lime . 
. 4 
•13 
