SECT. 2] CONTINENTAL SHELF AND SLOPE 297 



1953; Day, Hill, Laiighton and Swallow, 1956; Allan, 1961). The English 

 Channel is an epicontinental sea in which sediments have been deposited 

 since New Red Sandstone (Permian and Triassic) times. As in eastern 

 North America, the shelf in the Channel, and the surrounding plains in South 

 England and in the French Bassin de Paris, belong to the same sedimentary 

 unit. In the emerged or coastal parts, several distinct depressions in the 

 Armorican basement, more than 10,000 ft deep, have been found in Hampshire 

 (Kent, 1949), in Champagne and in Lorraine (Cholley, 1960). In the Channel 

 proper, the deposition has also been more or less thick according to place 

 and period : for example, it seems that the Tertiary deposits occur in separate 

 small basins. Trias and Cretaceous cover large areas. Although the sedimen- 

 tation has been somewhat discontinuous, some 3000 ft of post-Carboniferous 

 strata seem to exist across the western part of the Channel between Brittany 

 and Cornwall ; in the Celtic Sea (Fig. 8d), they merge into a post-Carboniferous 

 synclinorium which becomes deeper and deeper to the SSW as far as the 

 edge of the continental shelf, where the Palaeozoic floor is found at about 

 10,000 ft below sea-level. Formerly, a Palaeozoic geosyncline extended to the 

 continental slope at least. Mesozoic and Cenozoic samples have been dredged 

 from three places on the continental slope in the Celtic Sea (Bourcart and 

 Marie, 1951 ; Day, 1959), which thus resembles the continental slope off eastern 

 North America (if the samples were in situ). 



The North Sea is another subsiding basin, separated from the former by a 

 buried ridge running from Charnwood Forest and East Anglia to Brabant and 

 the Ardenne shield. It includes North-east England, the Netherlands and 

 North-west Germany. According to Dutch geologists quoted by Umbgrove 

 (1945), the post-Carboniferous sedimentation would reach 7500 m and perhaps 

 9000 m in some parts ; some 6000 m are assumed to occur under Liineburg near 

 Hamburg ; the Pleistocene alone is more than 600 m thick in West Holland 

 (Pannekoek, 1956). Recent seismic prospecting on the Dogger Bank (Stride, 

 1959) points to sediments more than 11,400 ft thick (3400 m) above the base- 

 ment (thickness of supposed Pleistocene 1250 ft; Cenozoic 1850 ft; Mesozoic 

 and possibly Pennsylvanian more than 8300 ft). A resemblance between the 

 North Sea basin and the Gulf Coast geosyncline lies in the salt domes rising 

 from the deepest parts to the surface, in Friesland, Germany and Louisiana. 



Although the data concerning the continental shelves of western and north- 

 western Australia are very sparse, Fairbridge has tried to gather the avail- 

 able material into a provisional synthesis (Fairbridge, 1953; Carrigy and 

 Fairbridge, 1954), from which it results that large parts of these areas, where 

 the shelf is 24 to 250 miles wide, seem to belong more or less to the type con- 

 sidered here (Fig. 9). The advance in geological knowledge on land in western 

 Australia, clearly summarized and discussed by Teichert (1958), indicates that 

 four large sedimentary basins (Bonaparte Gulf, Canning, Carnarvon and Perth), 

 in which maximum thicknesses of sedimentary rocks reach from 17,750 to 

 40,000 ft, occur in this part of the continent, and are widely open to the sea. 

 The Pre-Cambrian basement rises as blocks between them. The sequences are 



