118 Mr. D. Sharpe on the Geology of 



surface of that part of the country. On the south side of the fault, the calcareous 

 beds of the middle division rise into the bold abrupt hills which form the eastern 

 end of the lines of Torres Vedras, while on the north side the uppermost sand- 

 stones occur, overlaid by the Hippurite limestone ; and they form the surfaces of 

 the country to the northward. Judging from appearances, this fault extends a 

 long way into the interior ; but I followed it only four miles, from Alhandra to 

 Trancozo. 



One of the upper beds of the calcareous division resembles so closely the usual 

 character of the Hippurite limestone, that I could not determine whether the lime- 

 stone hill at Alhandra belongs to this formation, or is an outlying mass of that 

 limestone. 



The tract of red sandstone, next in importance, forms a narrow band, reaching 

 from the neighbourhood of Loures to Cape Sinchette. From its northern ex- 

 tremity to the Cascaes river the beds dip to the S.E., at angles varying from 20° 

 to 60°, and at Sabugo they are perpendicular. They consist principally of the 

 sandstones of the upper division, but the coloured marls are seen near Cacem, on 

 the Cintra road, and the calcareous beds occur where the deposit widens out to- 

 wards Sabugo ; the Mafra road crosses them in that neighbourhood for about three 

 miles ; they occur also between Manique and Cascaes. 



The Cascaes river follows the line of a considerable fault, and on its western side 

 the calcareous beds are exposed with a prevailing dip of 5° or 10° to the south : in 

 this neighbourhood also the strata are disturbed by many small faults. 



The red sandstone ranges, on the south of the Tagus, from near Palmella and St. 

 Ubes to the coast north of Cape Espichel. The strike of the beds is nearly from 

 E.N.E. to W.S.W., and their usual dip N. or N.W., at a high angle : this part of 

 the formation has been dislocated by many considerable faults, but as they aflfect 

 also several of the older rocks, all the disturbances of this neighbourhood are de- 

 scribed together. (See p. 129, et seq.) 



The upper division of the formation is better exposed near Palmella and St. Ubes 

 than in any other part which I examined, except the hills behind Bellas north-west 

 of Lisbon ; it consists here of 



1. Very ferruginous loose sand and gravel. 



2. Fine sandstone, sands and marls of various colours. 



3. Ferruginous sandstones. 



The gravel is more abundant than usual, occupying some picturesque valleys 

 between Azeitao and St. Ubes ; while the adjacent barren Serrade San Luiz, con- 

 sisting of the succeeding beds of the same formation, rises abruptly to more than 

 1200 feet above the sea. 



The calcareous beds may be traced from the coast on the north side of Cape 



