ACADEMY OF SOENCES J AFRICA. 51 



pare these pipes with the "volcanic embryos" and melilite-basalt-intrusions in Southern 

 Bavaria, though the analogy is not a very close one (Branca '94, Schwarz '05). 



In the absence of information concerning conditions of intrusion we need here merely men- 

 tion the occurrence of gabbro and peridotite in British Central Africa (Prior '03) (Bull. Imp. 

 Inst. '04), of gabbro in Togoland (Koert '10), and of gabbro-peridotite series of French Guinea 

 (Lacroix '11) to which probably belongs the enormous noritic intrusion of the peninsula of Sierra 

 Leone (Dixey '21). The basic rocks of northwestern Africa (Atlas Mountains) have already 

 been described. 



In the southeast of Egypt Ball ('12) has noted among the schists of the Red Sea Hills a 

 group of granites associated with gabbros and serpentinized ultrabasic rocks which cover 

 more than 200 square miles. There is little evidence of the conditions of their intrusion. 



