190 JOSEPH THOMSON ON THE aEOLOGY OF [May 1 899, 



11. The Geology of Sotjthekn Morocco and the Atla.s Mountains. 

 By the late Joseph Thomson, Esq. (Communicated by the 

 Peesident. Read January 18th, J 899.) 



Contents. Page 



I. Introdactory Eemarks 190 



II. Geographical Sketch of Southern Morocco and the Atlas 191 



III. The Coastal Lowlands 194 



IV. The Plateau 196 



V. The Atlas Mountains 198 



(1) The Wad Demnat. 



(2) The Wad G-adat. 



(,8) The Mountains in Glauwa and Misfiwa. 



(4) The Wad Urika. 



(5) The Wad Eeraya. 



(6) From Amsmiz across Gindafy to Sus. 



(7) The Asif el Mel. 



(8) From Imintanut to Sus. 



I. Inteodtjctort IIemarks. 



Among the curious facts of the 19th century there are few things 

 more notable than our comparative ignorance of the geography and 

 geology of the Empire of Morocco. Here is an extensive country 

 within sight of Europe, and even within sound of the guns of a 

 British garrison-town, about which we in many respects know less 

 than about many districts in the remotest depths of the African Con- 

 tinent. "Within recent years something has beeu done to dispel our 

 ignorance of the geography of Morocco, but geologically our knowledge 

 of it remains almost at a standstill. 



Previous to the expedition of Sir Joseph Hooker to the Great 

 Atlas in 1871, hardly a single ray of light had been thrown upon 

 the stratigraphical constitution of Southern Morocco, and since that 

 time barely one trustworthy fact has been added to the sum total. 

 Practically the geological literature of Southern Morocco consists of 

 a paper by Mr. Maw, who accompanied Sir Joseph, entitled ' IS'otes 

 on the Geology of the Plain of Marocco & the Great Atlas,' and 

 published as an appendix to Hooker & Bali's ' Tour in Marocco & 

 the Great Atlas.' ^ 



In the beginning of 1888 I conceived the idea of attempting the 

 exploration of the less known parts of the Moorish Empire, and 

 especially of the Atlas Mountains. In pursuit of this enterprise I 

 left England on March 9th, returning home towards the end of 

 October, successful beyond my expectations so far as the Atlas 

 and Southern Morocco are concerned. I was enabled to cross the 

 range in several new directions, and ascend heights never before 

 achieved, with the result that a clearer and more accurate notion of 

 the geography of the Atlas has been secured. 



But while geographical exploration was my special object, and 

 largely absorbed my attention and time, I was not unmindful of 

 the claims of geology, nor forgetful of its intimate connexion with 

 geography. In venturing now to bring together my geological 



1 [London, 1878. Appendix H, pp. 446-467, with 6 figs, in the text, & 

 horiz. sect.] 



