these materials England is at present dependent
upon foreign countries, and the high price of guano and of bones
prevents their general application, and in sufficient quantity.
Every year the trade in these substances must decrease, or their
price will rise as the demand for them increases.

According to these premises, it cannot be disputed, that the annual
expense of Great Britain for the importation of bones and guano is
equivalent to a duty on corn: with this difference only, that the
amount is paid to foreigners in money.

To restore the disturbed equilibrium of constitution of the
soil,--to fertilise her fields,--England requires an enormous supply
of animal excrements, and it must, therefore, excite considerable
interest to learn, that she possesses beneath her soil beds of
fossil guano, strata of animal excrements, in a state which will
probably allow of their being employed as a manure at a very small
expense. The coprolithes discovered by Dr. Buckland, (a discovery of
the highest interest to Geology,) are these excrements; and it seems
extremely probable that in these strata England possesses the means
of supplying the place of recent bones, and therefore the principal
conditions of improving agriculture--of restoring and exalting the
fertility of her fields.

In the autumn of 1842, Dr. Buckland pointed out to me a bed of
coprolithes in the neighbourhood of Clifton, from half to one foot
thick, inclosed in a limestone formation, extending as a brown
stripe in the rocks, for miles along the banks of the Severn. The
limestone marl of Lyme Regis consists, for the most part, of
one-fourth part of fossil excrements and bones. The same are
abundant in the lias of Bath, Eastern and Broadway Hill, near
Evesham. Dr. Buckland mentions beds, several miles in extent, the
substance of which consists, in many places, of a fourth part of
coprolithes.

Pieces of the limestone rock in Clifton, near Bristol, which is rich
in coprolithes and organic remains, fragments of bones, teeth, &c.,
were subjected to analysis, and were found to contain above 18 per
cent. of phosphate of lime. If this limestone is burned and brought
in that state to the fields, it must be a perfect substitute for
bones, the efficacy of which as a manure does not depend, as has
been generally, but erroneously supposed, upon the nitrogenised
matter which they contain, but on their phosphate of lime.

The osseous breccia found in many parts of England