1872.] MAW — vi.Aiyi OF moeocco. 93 



The form of the mounds in the valley west of Tassemarout at once 

 conveyed to me the impression that they were of glacial origin ; and 

 the discovery of undoubted moraines in the higher valleys strength- 

 ened my conviction that the Boulder-mounds and ridges flanking 

 the Atlas plateau can only be satisfactorily explained as the result 

 of glaciers covering the escarpment, leaving on their recession the 

 intermediate depression. 



(b) Moraines of the liiglier Atlas. — Kindred phenomena occur 

 higher up in the Atlas vaUeys, most notable in the case of unques- 

 tionable moraines, commencing at the village of Eitmasan in the 

 province of Eeria, at an altitude of 6000 feet. Here we met with a 

 gigantic ridge of porphyry blocks, having a terminal angle of re- 

 pose of between 800 and 900 feet in vertical height, and grouped 

 with several other mounds and ridges of similar scale, all composed 

 of great masses of rock with little or no admixture of small frag- 

 ments, and completely damming up the steep ravine and retaining 

 behind it a small alluvial plain 6700 feet above the sea-level. 



We failed to detect any scratched blocks or strise ; but that these 

 ridges are true glacial moraines no one who has seen them and com- 

 pared them with other glacial phenomena, would for a moment 

 doubt ; and their interrupted occurrence at various heights is strictly 

 in accordance with the distribution of moraines in many of the 

 Swiss and Scotch valleys. 



(c) Stratified Red- Sandstone and Limestone Series. — A long line 

 of comparatively low and flattish hills, forming a plateau, with an 

 average height of about 4500 feet above the sea, and 2800 feet above 

 the plain of Morocco, intervenes between it and the main ridge of 

 the Atlas. The edge of this plateau facing the plain is for some 

 distance an escarpment, exposing stratified beds of limestone con- 

 taining bands of chalcedonic concretions, underlain by grey and puce- 

 coloured marls. As this plateau is crossed from north to south 

 toward the Atlas ridge, its central line would represent a synclinal, 

 from which the beds rise northwards towards the plain and south- 

 wards towards the Atlas ; but it is locally broken and contorted, and 

 near Tassemarout the limestone beds stand up nearly on end. South 

 of the synclinal, i. e. between the centre of the irregular plateau and 

 the Atlas, great deposits of Red Sandstone and dark- red conglomerate, 

 interstratified with cream-coloured shelly limestone, occur, which 

 appear to be inferior members of the same series as the limestone and 

 marls exposed in the escarpment facing the plain. From the few 

 obscure fossils, including an Ostrea, I was able to collect from the 

 limestone bands, Mr. Etheridge considers that they are of Cretaceous 

 age. They are, like the beds of the plain, remarkable for contain- 

 ing great deposits of chalcedonic concretions ; but the latter may 

 possibly be of more recent age. They rest unconformably on the 

 upturned edges of grey shaly beds, and extend also over the por- 

 phyries that form the great mass of the Atlas chain. They ap- 

 pear to have been deposited subsequently to the porphyry-ridge 

 assuming its present hill-and-vaUey contour, as little isolated frag- 

 ments are seen clinging to the sides of a narrow ravine leading 



