1849.] SHARPE ON THE SECONDARY ROCKS OF PORTUGAL. 161 



Having only traced the Coimbra limestone and sandstone for a few 

 miles from that city, I am not aware how far they extend either to 

 the north or south. The Serra de Busaco has been described to me 

 as consisting of a sandstone resting on micaceous schist, and as this 

 range of hills is exactly on the line of the Coimbra sandstone, it is 

 possible that the sandstone of Busaco may belong to the same forma- 

 tion, although some specimens from that locality in the Museum at 

 Coimbra have a metamorphic appearance. 



The limestone of Coimbra is separated from the Jurassic limestone 

 chain west of Condeixa by several miles of flat country covered by 

 subcretaceous beds. Until the organic remains have been examined, 

 it cannot be determined whether it is strictly identical with any of 

 the otherjurassic limestones of Portugal ; it is however not improbable 

 that the Coimbra sandstone may prove identical with the sandstone 

 which near Buarcos overlies the carboniferous series of Cape Mondego, 

 which belongs to the oolitic period and vrill be next described. Till 

 this is ascertained, we must be content to class the Coimbra limestone 

 and sandstone in the Jurassic system without determining their exact 

 place in the series. 



Limestone and Coal of Cape Mondego. 



It has been mentioned p. 147, that below the red sandstone of 

 Buarcos, referred to the subcretaceous period, there is another bed 

 of sandstone, of the oolitic period, connected with the coal and lime- 

 stones of Cape Mondego : a good section of these beds is seen along 

 the coast between Buarcos and the extremity of the Cape, exhibiting 

 the following series in descending order : — 



1 . Red sandstones vrith some beds of marl, commencing a little 

 west of Buarcos, where they dip E.S.E. 15° ; farther west the dip is 

 S.E. 40°. These sandstones appear to be the uppermost Jurassic rocks 

 seen in this neighbourhood. 



2. A series of sandstones of various characters containing a few thin 

 beds of impure limestone, which become more important in the lower 

 portion. 



3. Coarse limestone about 100 feet thick with some partings of 

 sandstone with abundance of small oysters and other shells, dip S.E. 

 40°. 



4. Sandstone of great thickness with some thin beds of limestone, 

 containing Ostrsea, Terebratula, &c., dip S.E. 40° ; in the lower part 

 the limestones are thicker and more frequent. 



5. Carboniferous series, viz. : — 



a. Alternate thin beds of marl, limestone and sandstone, 15 feet. 



h. Coal, 2 feet. 



c. Alternations of white limestone and grey marl, 12 feet. 



d. Coal, 1 foot. 



e. Marl and sandstone, 5 feet. 



f. Coal, 6 inches. 



g. Carbonaceous shale alternating with limestone, 6 feet. 

 h. Coal, 1 foot. 



i. Alternations of shale and limestone, 8 i^ot. 



