294 



GUILCHER 



[chap. 13 



Peterson, 1950). In sections parallel to the coast, the depth of the basement is 

 not regular: it decreases greatly on the "Carolina ridge" (south of North 

 Carolina), and increases again farther south ; however, the seaward thickening 

 of the strata is a general feature of the coastal plain. In the su])nierged ])art, 

 the structure is the same, since Cretaceous, Eocene, ^Miocene and Pliocene have 

 been found in the canyons encroaching on the shelf edge in the Georges Bank 

 region (Stetson, 1949). The benches breaking the general declivity of the 



NW 



Long Islond section 







P?3=^^^ 



Sec level 



SE 



C 10,000- 

 20,000 



.Woter 



r v.vv j Unconsolidated 

 t-:-:-:'j sediment 



Semiconsolidated 

 sediment 



20 40 60 80 100 120 140 

 Nautical miles 



^ Consolidoted 

 sediment 



NW Halifax section 



V'H>^ Crystalline 

 basement 



i'^V/V, Sub -basement 



Newfoundland 

 C.St. l\^ory 



NNE 



Nautical miles 



(c) 



Grand Bonks 



Sea level 



SSW 



wsw 



100 200 



Nauticol miles 



Celtic Seo section 



300 



Water 



t r I III IA..„..,n hasementi,,.,^— X— ---- 



P e - Per mianboseme^,,.^^-;^^^ 



300 



J L 



200 



J_ 



J I I L 



100 80 60 40 20 



(d) 



10,000 - 

 20,000 



Nouticol miles 



Fig. 8. Probable geological structure of the shelf and slope in north -eastei'n North America 

 and in North-west Europe (Celtic Sea), according to geophysical investigations. 

 (After Ewing, Bentley, Officer, Press, Steenland and Worzel, 1950-1954-1956, for 

 America; after Day, Hill, Laughton and Swallow, 1956, for Europe.) 



continental slope are likely to be structural : they have been correlated, be- 

 tween Cape Hatteras and Cape May, with the formations encoinitered in the 

 Hatteras drilling, and the same interpretation is proposed for other benches 

 along the Blake Escar])ment from which sediments of Recent to Upper Creta- 

 ceous were obtained (Heezen, Tharp and Ewing, 1959, pp. 46-48). On the 

 other hand, careful and numerous geophysical investigations (Ewing et al., 

 1937 to 1956; Hersey et al., 1959) have revealed the topography of the base- 

 ment under the sedimentary strata along a number of transverse sections 



