1849.] SHARPE ON THE SECONDARY ROCKS OF PORTUGAL. 147 



ginous sand and coarse sandstone striking nearly E. and W. which 

 continues to Buarcos : this sandstone is overlaid by a formation of 

 hard whitish argillaceous limestone between 1 00 and 200 feet thick 

 which dips S.S.W. 15°, and forms the northern bank of the Mondego 

 for about six miles, extending from the fort at the entrance of the 

 river, and passing under the little town of Figueira to the first great 

 bend of the river : during this course, the limestone rises from the 

 water's edge to the top of the hills which bound the river. If con- 

 tinued in the same direction to the eastward, the Figueira limestone 

 would cross the Mondego and extend towards Soure, through a part 

 of the country which I did not examine. 



The Figueira limestone is rich in fossils, but it is so hard that they 

 are not easily extracted ; the following were found between the town 

 and the fort : — 



Exogyra conica, Sow. Echinopsis subuculus, n. s. 



Gryphsea columba, Lam., very abundant. Cidaris Iseviuscula, Agassiz. 



Pecten Dutemplei, D^Orb. Toxaster Couloni?, Jgassiz. 



Turritella Vibrayana, D^Orb. Brissus subdepressus, n. s. 



Turbo Mundae, n. s. Scalaria, fragments. 



Tylostoraa Torrubise, n. s. Turritella, fragments. 

 Nerinsea Mundae, n. s. 



These species indicate that we are still in the upper portion of the 

 subcretaceous series. The most abundant and characteristic shell in 

 this locality is the Gryphcea columba, which I have not met with 

 elsewhere in Portugal. In mineral character and in its greater thick- 

 ness and compactness, the Figueira limestone differs from all the beds 

 of subcretaceous limestone yet described, which, added to some differ- 

 ence in organic remains, makes it probable that it is a different bed. 



There is a good descending section along the coast from Figueira 

 to Cape Mondego in the following order : — 



Figueira limestone, dip S.S.W. 15°. 



Calcareous sandstone, dip S.S.W. 15° (a few feet only). 



Soft light brown sandstone, dip for about one mile S.S.W. 15°, 

 then changing gradually to S.S.W. 10°; this sandstone passes into a 

 hard, dark, ferruginous, calcareous conglomerate, and then into a hard 

 red grit, dip S.S.W. 10°, on which stands the village of Buarcos. 



West of Buarcos are various red sandstones of softer character, with 

 occasional alternations of red marl, dipping first E.S.E. 15°, and then 

 S.E. 40° ; these rest on a series of beds of sandstone alternating with 

 limestone, the organic remains of which belong to the upper part of 

 the oolitic series ; below this is the coal series of Cape Mondego 

 resting on limestones indicative of the middle portion of the oolites, 

 which will be described in detail farther on. 



There is a gradual passage from the Figueira limestone down to 

 the sandstone of Buarcos ; so also there is a passage from the sand- 

 stone west of Buarcos down to the base of the Jurassic series of Cape 

 Mondego ; and if this section alone were considered, it might be 

 thought that we had here a passage from the subcretaceous to the 

 Jurassic formation ; but this cannot be the case, for as we proceed 

 southward we shall meet vdth subcretaceous beds of an older date 



