272 GEOLOGY. 



much greater than the area where it is exposed, since it is covered in 

 many regions by younger formations. The Cambrian, however, is not 

 believed to underlie the younger strata of eastern Russia, and this part 

 of the continent is believed to have been mostly out of water during 

 the Cambrian period. 



The Cambrian strata of Europe, especially of western Europe, are 

 often much folded. In some regions also (Britain and Brittany) igneous 

 rocks occur at or near the base of the system. In central and eastern 

 Europe, on the other hand, the formations are essentially horizontal. 

 Beds of clay which are still plastic, and be^s of sand which are still 

 uncemented, are here found within the limits of the system. 



No geographic change of great importance seems to have marked 

 the close of the Cambrian. In this respect, as in others, the Cambrian 

 history of Europe and North America are in general correspondence. 



Other countries. — By means of their fossils Cambrian rocks are 

 known to occur in the northeastern parts of China, 1 in the Salt range 

 of India 2 (Lower and Middle Cambrian), in the southeastern part of 

 Australia 3 and in Tasmania (Lower, Middle, and Upper), and in the 

 northwestern part (Salta) of Argentina 4 (Upper Cambrian). In most 

 of these regions the formations have not been studied in much detail. 



Glacial formations. — In the vicinity of Varanger fjord, in northern 

 Norway, Lat. 70° 8' N., there is a bed of bowlder-bearing rock rest- 

 ing on a smoothed and striated pavement of the distinctive glacial 

 type, and embraced within an irregular clastic formation, known as 

 the Gaisa beds. 5 These beds rest upon the eroded surface of a crystal- 

 line terrane. No fossils have been found in them and their age is 

 not positively determined. Reusch regards them as equivalent to 

 the Sparagmite formation in central and southern Norway which 

 underlies beds containing the Olenellus fauna, and which is therefore 

 either the very earliest Cambrian or earlier. The Gaisa beds bear 

 some resemblance to the Torridon (Proterozoic) of the British Isles 

 and may be of the same age. They are of the red sandstone type, 



1 Von Richthofen, China, Vol. III. 



2 Redlich, Palaeontologica Indica, new ser. Vol. I, and Records Geol. Surv. of 

 India, Vols. XXII, XXIV, and XXVII. 



3 Etheridge, Proc. Roy. Soc. Tasmania, 1882-1883; Trans. Roy. Soc. Australia, 

 Vol. XIII; Tate, Ibid., Vol. II, XLVIII, and XV; and Johnston, Surv. of Tasmania. 



4 Kayser, Zeit. der deutsch. Geol. Gesell., Vol. XLIX. 



5 Reusch, Norges geologiske Undersoegelse : Det nordlige Norges Geologi, 189! 

 Also Strahan, Quar. Jour. Geol. Soc, Vol. 53, 1897, pp. 137-146. 



