the Neighbourhood of Lisbon. 129 



the positiou of all the formations near the granite, both with reference to that rock and to each other. In 

 Nos. 2 and 5, extending north from the granite, the three lowest formations, the San Pedro limestone, the 

 shale, and the Espichel limestone are seen greatly elevated, and dipping from the granite at angles varying 



from 20° to 80°. 



The coast being very rough, I could not trace Section 5 so far as the preceding one, but the two agree 

 to the extent they can be compared. In these sections and in No. 4 all the beds of Espichel limestone 

 have not been equally affected ; and from some cause not apparent, there is another line of elevation 

 parallel to that caused by the granite, which has raised some of the beds of limestone into a saddle. 



In Sections 1 and 7, which show the south-east and south sides of the chain, the San Pedro limestone, 

 shale, and Espichel limestone are also raised by the granite, dipping from it at angles varying from 30° to 

 70°, the angle always increasing as the bed approaches the granite. Around these two sides of the hills 

 the disturbing forces have been fewer, and the elevation of the three formations is very regular. 



Section No. 4, drawn from the palace at Cintra to the N.E., offers irregularities which require parti- 

 cular notice. The San Pedro limestone is raised into a saddle, and the slate-clay dips from it on both 

 sides, abutting against the granite, below the palace. The form of the whole mass of granite being 

 nearly triangular, the strata which rest upon it have two principal lines of strike, parallel to the northern 

 and south-eastern edges of the granite range ; these two lines meet at a sharp angle just below the town 

 of Cintra, and at their point of intersection the beds are forced up into a saddle, accompanied by several 

 minor dislocations, one of which is shown in Section 4. 



As the sections round the granite agree in representing the three oldest formations as resting at high 

 inclinations upon that rock, we must conclude, that the granite was elevated to its present position after 

 the deposition of the Espichel limestone, the newest of those formations. 



Let us now examine the question with regard to the next formation, the red sandstone. Section 2 

 represents the sandstone resting nearly horizontally upon the elevated beds of Espichel limestone, and 

 the Mant of conformity is the more apparent, as the sandstone rests upon the basset edges of the lime- 

 stone, and dips in a contrary direction. There is also a want of conformity between the same beds on 

 the south side of the Cintra chain. These two sections prove conclusively, that the sandstone was depo- 

 sited after the elevation of the rocks below it, and after the granite had assumed its present height. There 

 are, however, other sections bearing upon the case ; in No. 4, the beds of sandstone are almost conform- 

 able with the uppermost beds of the limestone, but the beds of both rocks are so nearly horizontal, that 

 no argument can be drawn from them. In Sections No. 1 and 7 there is also a conformity between these 

 two formations, the sandstone dipping from the granite at angles of 20° and 30°. This seems to militate 

 against the conclusion just drawn ; but the map shows, that tliese sections cross that ridge of sandstone 

 hills extending from Cascaes to Loures, which has been proved to have been raised at a later period by 

 the basalt ; and their inclined position is thus accounted for without reference to the eruption of the 

 granite. We may therefore assume that the granite-hills of Cintra were elevated to their present position 

 between the formation of the Espichel limestone and that of the red sandstone. The change produced 

 by the granite upon the limestone in contact with it, has been already described at p. 123. 



Disturbance of the Strata between Palmella and Cape Espichel. (PI. XV. Sect. 1, 9, 11 to 13.) 

 The country between these two places forms so distinct a geological district, that its numerous disturb- 

 ances deserve to be described apart. Sections 9, 11, 12 and 13, are drawn nearly parallel to one another 

 across this district, to illustrate the dislocations of the strata, by exhibiting all the positions in which tlie 

 beds lie with respect to each other, and they show that there have been considerable elevations at four 

 distinct periods at least. 



1st. The unconformable manner in which the Espichel limestone rests upon the older red conglome- 

 rate, shows that the latter had been elevated before the deposition of the former. (Section 13.) 

 VOL. VI. — SECOND SERIES. S 



