File:The Quarterly journal of the Geological Society of London (12511844445).jpg

. 26 PROCEEDINGS OF THE GEOLOGICAL, SOCIETY. .Mar. 23,
The northern face, which stems the angry surges of the Atlantic,
is nearly perpendicular, and affords ample scope for observation.
The base is of red sandstone, — dip N.W. by N, Z. 7°. It is covered
conformably by the blue fossiliferous shale, and this is overlaid by
the tufaceous limestone.
The summit-ridge is extremely narrow ; it scarcely appears to be
20 feet across, and is crowned with an almost impenetrable copse of
thorns, growing out of the interstices of the solid limestone rock. It
is said that this circumstance induced Columbus to give it the name
of Monte Christi. The French afterwards gave it the name of La
Grange, from its resemblance at a distance to an enormous barn, by
which name it is now more generally known. The miserable vestige
of a once flourishing town of above three thousand inhabitants, built
at the foot of it, is all that retains the name of Monte Christi.
The rock- specimens from the different beds of the Grange, when
compared with those from the Hills of Samba at Cercado, appear to
be as nearly similar as could be expected for the distance they bear
from each other. The dip of the beds of the Grange is almost
identical with that of the beds of Postrero and Cercado. The blue
shale appears to be about 800 feet thick, covered by about 200 feet
of limestone in a tabular mass.
Fig. 7. — Section of the Cliff at the western extremity of the Grange
Mountain, showing the interlacing of the shales.
1
1. Blue sandy shale, fossiliferous.
2. Ferruginous calcareous shale, alternating with argillaceous sandy shale ; fossiliferous.
The cliffs at the western extremity of the Grange display an
interesting intercalation of the blue and the yellow shales (see fig. 7) ;
the latter is argillo-calcareous, and is, apparently, a large develop-
ment of what at Cercado is a thinner bed of 50 feet thick ; it ap-
pears, also, to be a modfied form of the calcareous shale so largely
developed at Angostura.
Fossils from the Sandstone plains. — These fossils were collected
at Inamagado, Esperanza, Rompino, Cerro Gordo, San Lorenzo, La
Salada, and Cana.
They are found scattered upon the surface of the sandstone plain
of the district of Santiago, usually half-buried in silt or coarse sand,