the Neighbourhood of Lisbon. 119 



Espichel to Cezimbra, and again in the cliffs of the Serra de Risco ; the lower sand- 

 stone division is visible only on the cliff, near the Chapel, at Cape Espichel : with 

 these exceptions, this district consists entirely of the beds of the upper division. 



The country occupied by the upper strata of this formation is generally intersected 

 by irregular valleys and ravines. The lower lands are fertile and wooded, but the 

 iiills are open and covered with heath : the calcareous rocks of the middle division 

 form wild dreary hills, hardly capable of cultivation : and the lower sandstone divi- 

 sion varies much, affording barren hilly districts and others of greater fertihty. All 

 the sandstones occasionally form extensive plains covered with pine-woods. 



The connexion of the red sandstone with the older rocks is exposed in few places 

 near Lisbon. On the north of Cintra the sandstone overlies all the older formations, 

 resting almost horizontally upon the inclined strata of Espichel limestone (Sect. 

 2 and 4), slate-clay, and San Pedro limestone, and upon the granite ; and on the 

 south of the Cintra hills, upon the Espichel limestone (Sect. 1 and 7). South of 

 the Tagus it lies, with every degree of want of conformity, upon the limestone of 

 the Serra de Arrabida, and upon the elevated peaks of the older red conglomerate 

 of the Covoens and the Serra de San Luiz (Sect. 11 to 13). 



Mineral Contents. 



Lignite has been found in this formation in many places, occasionally in sufficient quantity to lead to 

 unsuccessful search for coal : the principal localities are Ericeira, and the neighbourhoods of Torres 

 Vedras, Cascaes and Cape Espichel. I examined only the two last. 



The cliff, a little to the east of Cascaes, gives the following very good section of the lower beds of the 

 upper sandstone division : — 



1. Fine-grained white sandstone. 



2. Coarse sandstone, slightly sulphureous 5 feet. 



3. Coarse quartzose gritstone, very sulphureous 



i 



4. Thin layers of marl, separated by seams of vegetable matter, and containing abun- 



dance of sulphur and some iron pyrites , 1^ — 



5. Fine sandstone, with thin layers of lignite, containing impressions and pyritous casts of 



vegetables 1 — 



6. Bituminous marl, with sulphur ]i — 



7. Fine sandstone, very sulphureous 3 — 



8. Coarse sandstone, slightly sulphureous 5 — 



9. Hard compact sandstone, containing very little sulphur. 



The lignite varies from a quarter of an inch to eight inches in thickness. The sulphur effloresces from 

 some of the beds in great quantities. The vegetable impressions are fragments of leaves and stalks too 

 imperfect for determination; the only interesting specimens met with being small seed-vessels. The beds 

 have been thrown into great confusion at this spot by a basaltic dyke (PI. XV. Sect. 3 and 10). 



The lignite beds, near Cape Espjchel, occur in the calcareous division of the formation ; and the fol- 

 lowing section may be seen in the cliff, about a mile to the north of the Chapel : — 



Limestone, alternating with sandstone. 



Limestone , 3 feet. 



