152 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 21, 



At the Praia de Lagoa, near the preceding. 

 Natica praelonga, Deshayes. Pholadomya Royana?, UOrh. 



At the Praia de Adrarga, north of the Cintra hills. 



Nerinsea Archiraedis, D'Orb. Pecten striato-costatus, Goldf. 



cylindrica, Voltz. Trigonia caudata, ^^rasse^r. {T.scabra, 



Pyramidella sagittata, n. s. Morris's Catalogue.) 

 Ostraea colubrina, Lam. 



At Fontanellas, north of Cintra. 

 Cardium corrugatum, n. s. 



Both at the Praia de Adrarga and the Praia de Ma9ams the hme- 

 stones have been disturbed by various eruptions of trap, which appear 

 to have burst out during the formation of the subcretaceous beds, with 

 some of which they are very irregularly interstratified, while others 

 are displaced by them : in connection with the trap is a mass of ar- 

 gillaceous breccia, evidently of igneous origin and of considerable 

 thickness, which interrupts the series of stratified deposits. These 

 trappean beds are continued in a band round the Cintra hills, but 

 they do not belong to one formation, as described in my former paper 

 (Trans, vol. vi. p. 122), but pass through the different rocks which 

 encircle the granite. 



The beds of the calcareous middle division of the subcretaceous 

 series cover the country north of Cintra for many miles, extending 

 beyond Mafra and Ericeira, and resting upon ferruginous sands, which 

 on the Caldas road are met with before reaching Torres Vedras. 



The lowest part of the subcretaceous series is largely developed in 

 the district which lies to the north-east of Lisbon, bounded by the 

 Tagus from near Verdelha to Villa Franca. The great elevatoiy 

 movement which has thrown up the Jurassic rocks of Monte Junto 

 was continued with less intensity to the southward as far as Alhandra, 

 raising up all the lower beds of the subcretaceous series into an anti- 

 clinal of which the axis meets the Tagus at that place. This is seen 

 in section No. 4 (fig. 5), which shows the position of the beds along 

 the bank of the Tagus from Verdelha to Villa Franca. 



Fig. 5. 



Section No. 4. Bank of the Tagus near Alhandra. 



Limestone alternating with sandstone. Sand, g 



'3 2 a Subcretaceous Series. 



Tertiary. 



The same series of beds is crossed by the section No. 5 (fig. 6), 

 drawn nearly parallel to the last from Bucellas to Alenquer along a 

 line of traverse which I examined in some detail. 



From Bucellas to Befugidos, a distance of about seven and a half 



