Phosphorite in Estremadura. 
417 
given of its extent, which, though contradicted by M. Lc Play, 
in the memoir already referred to, still held their ground in the 
public mind, as the cursory manner in which that geologist 
alludes to the phenomenon was so far from setting the question 
at rest, that it even left us in doubt whether he, any more than 
his predecessor Proust, ever visited the locality. 
The former indeed underrates the magnitude of the deposit, 
as much as the latter exaggerates it ; for a rock varying from 7 
to 16 feet in breadth, traceable for nearly two miles along the 
surface of the ground, and extending into the earth to a great, 
though as yet an unascertained depth, cannot be regarded as 
either unimportant or inconsiderable. 
4thly. Because a statement of its chemical and mineralogical 
characters, as well as of its relations to the rock in which it 
occurs, mav lead to the discovery of it in other less distant and 
more accessible localities, and thus be the means of supplying 
a new source of phosphate of lime for agricultural purposes. 
Lastly. We have been induced to enter more fully into its 
nature and relations in consequence of the interest which it has 
lately excited amongst agriculturists. 
That it would prove equally efficacious as a manure with phos- 
phate of lime derived from animal sources, must not indeed be 
taken for granted too readily, until this point has itself been made 
the subject of direct experiment ; but there was a sufficient proba- 
bility that such would prove the case, to induce us to take some 
trouble in ascertaining the price at which it might be procured, 
and the facilities that might offer for transporting it to our own 
country. 
Were the Tagus now navigable up to Toledo, which, during 
the period when the crowns of Spain and Portugal were con- 
joined in the person of Philip II., it is said to have been the 
intention of the government to render it, two days' journey in the 
light carts of the country would convey the material to the least 
distant point on that river, near the broken bridge of Almaraz, 
But at present, such is the retrograde state of things in the 
Peninsula, that the Tagus is not now navigable even so far as 
the frontiers of Portugal. 
A still shorter distance separates the site of the phosphorite from 
the Guadiana, but much requires to be done before that river can 
be navigated even up to Badajoz. 
At present the only practicable route by which to transport 
the mineral in question to the coast seems to be the one which 
we ourselves had recourse to, namely, that to Seville, a journey for 
mules of at least six days ; this latter mode of conveyance, how- 
ever, though the most convenient one for small quantities, is so 
expensive, as to be quite out of the question on the great scale. 
