94 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [Jan. 10, 



out of the valley we ascended through the j)rovince of Reria to the 

 Atlas, Their relation to the few exposures of stratified beds in the 

 plain is somewhat uncertain, as no fossils were obtained in the 

 latter, and there are no direct connecting links ; but, judging from 

 petrological similarity, and from the fact that Neocomian fossils occur 

 in exposed beds on the coast-cliffs, and Cretaceous fossils in the beds 

 forming the crest of the plateau, it seems possible that an un- 

 broken series occurs from the cliff north of SafFe to the plateau 

 skirting the Atlas, representing the whole of the Cretaceous epoch ; 

 but it is also open to question whether the level beds of the plain 

 may not be an inland extension of the strata of Miocene age from 

 which Dr. Hooker obtained fossils at the Jew's Cliff south of Saffe. 



(d) Grey Shales. — At several points on entering the lateral vaUeys 

 of the Atlas, almost vertical shaly beds are crossed, having a strike 

 nearly east and west, corresponding with the trend of the chain. 

 They clearly underlie, and are unconformable to, the Eed-Sandstone 

 and Limestone series ; and their almost vertical position appears 

 connected with one of the several upheavals that have affected the 

 chain. Of their geological age there is no evidence, except that they 

 are pre-Cretaceous. In places, as at Assghin, they abound in nodules 

 of carbonate of iron. Pale shales, containing quartz veins, crop up 

 near the village of Prouga, in the plain south-west of Morocco, 

 which may possibly belong to this series ; and if the porphyries 

 forming the mass of the Atlas are contemporaneous, they are pro- 

 bably interbedded with these grey shaly beds. 



(e) MetamorpTiic Bodes. — The most important development of 

 metamorphic rocks in the neighbourhood of Morocco is on the north 

 side of the city. In its immediate neighbourhood, three miles to the 

 north-west, a low rugged hill occurs, composed of a very hard and 

 compact dark-grey rock, containing knotted white concretions elon- 

 gated in the line of stratification, which dips from 50° to 80° south- 

 west, the strike being north-west and south-east. The whole of the 

 north side of the plain is bounded by ranges of rugged hiUs of similar 

 form, and apparently rising from 2000 to 3000 feet above the plain. 

 We had not an opportunity of visiting them ; but, judging from their 

 outline, they are identical in formation with the hill close to Morocco. 

 We observed nothing in the Atlas resembling it. 



The only other metamorphic rocks that came under our notice 

 were : — first, white marble or metamorphic limestone, intercalated 

 with the porphyrites at the summit of the ridge of the Atlas south 

 of Arroond ; secondly, mica-schists, pierced by red porphyry dykes, 

 forming the mass of Djeb Tezah, a point 11,500 feet in height, and 

 15 miles further west, ascended by Dr. Hooker and Mr. Ball after 

 my return. It is possible that the mica-schists may be a portion of 

 the grey-shale series, metamorphosed by the intrusion of the por- 

 phyry dykes. 



(f ) Porphyrites. — Of the eruptive rocks of the Atlas, porphyrites 

 and porphyritic tuffs occupy by far the most prominent position, 

 forming the great mass of its ridge. 



On entering the lateral vaUeys, after crossing the vertical shaly 



