SECT. 2] 



SUBMARINE CANYONS 



489 



America. The studies of Boiircart (1959) and of his associates have resulted in 

 many interesting contour charts of these canyons (Figs. 8 and 9). Even before 

 these canyons were surveyed by the French geologists, Kuenen (1953) had 

 come to the conclusion that at least the Corsican and Riviera submarine 

 canyons were the submerged continuations of river-eroded canyons. The 

 newer surveys apparently confirm this opinion, at least so far as the shapes of the 

 canyons are concerned. As off Cape San Lucas, Lower California, and Carmel, 



-43° 20' 



-43° N 



4°30'E 



Canon de la 



Cossidagne 



du Planier 

 Canon du Cap Couronne 



5 20'E 



Fig. 9. The juncture between the submarine canyons off the French Riviera and those off 

 the Gulf of Lyons. Note the absence of any indication of a major break which should 

 be found if the canyons are respectively drowned river valleys and eroded by turbidity 

 currents as suggested by Kuenen (1953). Contour interval 100 m. (After Bourcart, 

 1959.) 



California, the entire slope is cut up into what appears to be a maturely eroded 

 subaerial joattern, very much like the mountain slopes on the adjacent land. 

 Canyon center cores reported by Bourcart (1959) (some taken while the writer 

 was assisting in the operation) indicated the jDresence of sand layers inter- 

 bedded between mud, as in many other submarine canyons. The wall rocks are 

 evidently crystalline along the deeply indented coast of Corsica and both 

 granite and metamorphosed Paleozoics were found by Bourcart along the 

 canyon walls off the Maritime Alps. The rather remarkable conformity between 

 the canyon heads and the west coast bays of Corsica (Fig. 8) is unique. Yet the 



