MOROCCO. 361 



limits the northern horizon of Marrakesh ; the Dj. Achchir. the Dj. 

 Karra, and siniihir smiril mountain ranges, present phenomena recall- 

 in<»- those of the Tanniis in-('iermany or tlie Siei'ra de Alcudiad, and 

 other mountains of (he Spanish ta1)l('-land. The similarity het\Yeen 

 these primitive mountains of Spain and those of Moi'occo is in general 

 very great, esjx'cially in so far as the older fornudions were overlaid 

 by more recent de})osits, consisting of strata entirely horizontal and 

 still undisturbed, but merely elevated. The older foruudions show 

 through the recent dej)osits only where rocks cai)ablc of more resist- 

 ance jutted U]), or wjicrr the recent formations yielded either to the 

 energetic erosion and dcmidation produced by running water in the 

 pluvial period, or to aerial demulation, which is almost th(> only force 

 active since the pluvial period. It is to this force — aerial denuda- 

 tion—that the formation of table mountains is to l)e attributed. 

 These occur frequently in the central belt of plain land and often stand 

 together in groups. The thickness of the overlying deposits is not 

 very great. So far as I could tell, it ])robably nowhei'e exceeds 100 

 meters. Concerning the chronology of its fornudion, sufficient paleon- 

 tologic evidences are still lacking. On my hist trip I brought fossils 

 from Schedma — that is, from the extreme southwest — where disturb- 

 ances connected with the upheaval of the Atlas are still important 

 factors. E. Ficheur. who probably possesses the greatest knowledge 

 of the geologic construction of Algeria, ascribed these fossils to the 

 C^retaceous period. (Joing uj)on this assumption, I am of the opinion 

 that the winding valley of the Tensift, which I followed in 1890 ahnost 

 from its mouth to the sub-Atlantic high plateau at Marrakesh, was 

 cut into this rock. According to A.Brives, state geologist in Algeria, 

 and the first geologist to explore a portion of the Atlas Vorland, in 

 the winter of 1901-2, the overlying mountains between the Tensift 

 and the Um-er-Iibia, and north of this region, are to be ascribed for 

 the most part to the Miocene period. The investigations of this geol- 

 ogist in Morocco are known only through a preliminary publication. 

 Accordingly, the Atlas Vorland for the most part has the character 

 of stratified table-land. The dominating feature is that of plains — in 

 fact, high plateaus. As far as our present knowledge goes, it may 

 be assumed that two periods of uplift occurred, the one in Eocene 

 and the other in Quaternary time. Consequently there are two 

 levels — the coast plains and the high inland plateau — which comprise 

 the greatest portion of the Vorland. The coast ])lain, whose geologic 

 conditions I was able to distinguish clearly in my last trip (1901), 

 begins at Cape Hadid, 20 kilometers north of Mogador, in a narroAv 

 jioint. At the foot of Dj. Adnlar, Avhich is the dominating landmark 

 of central Morocco — that is, at Sidi Rehal — where the nnich-traveled 

 caravan route from Mazagan to Marrakesh, in the valley of IVItal, 

 climbs up to the higher level, the coast plain reaches its greatest 



