od 
shells occur, and Mr. Sharpe has been able to identify some of the 
latter with the Perna rugosa, Trigonia literata and Terebratula in- 
termedia, of the English secondary oolitic series. 
(f.) Espichel Limestone.—This formation constitutes the flat, outer 
band which encircles the Cintra hills, also the range of hills be- 
tween Cape Espichel and Cezimbra, and most probably the Serra 
d’ Arrabida near St. Ubes. At the first of these localities, it consists 
of thick beds of gray coarse limestone, alternating with thinner ones 
of shale or marl; at the second, of a similar limestone with fewer 
layers of shale; and at the Serra d’Arrabida, of compact gray lime- 
stone with no partings of shale, except towards the bottom of the 
formation. Around the hills of Cintra, the strata dip as from a 
centre, at angles varyimg from 20° to 75°; between Cape Espichel 
and Cezimbra their inclination is from 45° to 70° to the north; and 
in the Serra d’ Arrabida the prevailing dip is also to the north at a high 
angle, but at the west end of the Serra it varies from north to north- 
west and north-east; whilst in the northern side of the Serra de 
Vizo, or the eastern prolongation of the Serra d’Arrabida, the dip 
is toward the south. In the Cintra district the limestone rests con- 
formably on the subjacent formation of shale ; between Cape Espi- 
chel and Cezimbra, and in the Serra d’Arrabida the bottom beds 
are not exposed, and consequently the connexion withthe inferior de- 
posits is not visible ; but in the Serra de Vizo the limestone reposes 
quite unconformably upon highly inclined strata of the older red con: 
glomerate. The organic remains of this formation are principally 
casts of shells, which are not easily separable from the matrix. One of 
the specimens obtained by Mr. Sharpe closely resembles a Trigonia 
from the green sand of Blackdown. 
(g.) Shale.—The upper portion of this deposit consists princi- 
pally of shale, varying a good deal in character; the middle of 
indurated shale alternating regularly and conformably with beds 
of trap from five to twenty feet thick, and the lowest of dark shale. 
Near Ramalhao, where the formation is best displayed, there are 
from twenty to thirty distinct alternations of igneous rocks and shale, 
the latter being altered and indurated ; but in the cliff at the Praia de 
Adraga, where the deposit is diminished to about 200 feet, there is 
only one bed of igneous origin. The formation rests with perfect 
conformity on the San Pedro limestone, dipping on all sides from the 
central granite axis of Cintra, at angles from 30° to 60°. 
(h.) The San Pedro Limestone forms an inner zone around the 
Cintra hills, resting upon the granite. The upper beds are dark 
gray and earthy; but as the limestone approaches the granite, 
it gradually passes into a crystalline marble. At the village of 
San Pedro the following series is exposed :— 
Dark gray compact limestone several hundred feet 
chicky) 
Gray limestone with very slight traces of crystalline 
texture, and towards the bottom granular...... 200 feet 
Coarse crystalline marble, white or gray and white 100 
f 
