f)6 Oil the Phos})horic Strata of the Chalk Formation. 
in sufficient abundance to be profitably nsed as substitutes for bones. 
It was in etiect the resuscitation of the discovery originally made 
through the analysis of M. Berthier, nearly thirty years since. 
The circumstance which primarily induced our investigation 
into the nature of the peculiar green band of the upper green- 
sand was the extraordinary fertility noticed in the crops where 
the outcrops of this singular marl occurred. Attention was first 
attracted to the properties of this soil at Farnham, in Surrey, 
where pits have been sunk, and collections of specimens have 
been made, with a view to the full elucidation of the subject. As 
it was from specimens of soil obtained from this place and its 
immediate vicinity that various analytical examinations were made 
for the purpose of ascertaining their chemical ingredients, it may 
be well, in the first place, to detail such facts connected with the 
external properties, or agricultural relations, of this marl as have 
been noticed about Farnham, and the results obtained by che- 
mical analysis ; and afterwards point out such particulars of this 
bed in other places as have come under our personal inspection. 
In the parish of Farnham the bed traverses its whole extent from 
east to west, coinciding with the line of the very best hop-grounds — 
those which are perennially continued under hop culture. This is a 
remarkable circumstance, tending to confirm the opinion of the profuse 
abundance of phosphoric acid in the soil, as well as the facility with 
which the hop-plant appears to be able to assimilate the acid as it 
naturally exists. For the analysis of the hop proves it to be a great 
consumer of phosphoric acid, annually carrying oti' from the soil many 
pounds per acre, in addition to the quantity which is abstracted by the 
haulm and leaves, as is shown by the elements of the plant. It is 
not intended by this remark to convey the impression that the luxuriance 
of the crops on these particular soils is exclusively dependent on the 
amount of phosphoric acid which they contain, but as taken in con- 
junction with other fertilising substances, which the analysis shows to 
be co-existent in these soils. It has been also generally observed that 
in wet summers the growth of the bine of the hops upon these outcrops 
is too luxuriant, and consequently injurious to the crop, whicii invariably 
ripens later oa tliese spots. In dry summers, on the contrary, the crops 
are unusually and conspicuous-ly large : 28 bul^hels of hops were once 
picked on four consecutive hills on the site of one of the richest of the 
fossiliferous green beds, being at the rate of u])wards of 4 tons per acre, 
or ten times the average growth of the best soils. Near this place a 
few years ago the top or vegetable soil was removed from a few jierches 
of ground ; and when afterwards the land was replanted with hops, they 
grew as well as before, without any surface-soil: this spot, too, was the 
site of a fossil deposit. Another instance may be adduced in proof of 
the unusual fertilising property of the green bed, in a field also planted 
with hops, where the superficial soil consisted of diluvial drift gravel 
al)out two feet thick. This field, contrary to expectation, on account of 
the riuautity of surface- gravel, has proved to be well adapted for the 
