LAND AND WATER 23 



but in the Cambrian deposits there appears a very complete 

 fauna which the famous geologist Joachim de Barrande 

 regarded as the oldest of all, and to which he gave the name of 

 primordial fauna. 



The sea at that time occupied an area almost equal to that 

 which it occupies to-day ; the diminution of the earth's 

 diameter has since then perhaps increased its depth to a certain 

 extent, but it was probably very little different then from what 

 it is to-day. The transversal inter-continental channel was a 

 kind of English Channel, and not very deep, its coasts rose in 

 a very gentle slope, for we still find on the surface of the sand- 

 stone traces known as ripple-marks, left on the sand by the 

 action of the waves. The west coast of America was, so to 

 speak, staked out by three islands running parallel to its future 

 coast, and practically occupying the site of the Rocky 

 Mountains of Canada, the Sierra Nevada, and the Chilean 

 Andes. In the same way a southern peninsula of the Pal«- 

 arctic continent outlined the future Appalachians up to the 

 neck of the isthmus connecting the persisting area of emersion 

 called by Suess the Canadian barrier, with the continental 

 mass of which it formed the western and southern extremity. 

 The sea had abandoned the region of the Great Lakes situated 

 between Canada and the United States (Map I). 



Thenceforward these new lands were subjected to erosion ; 

 the crystalline rocks became decomposed by the action of the 

 sea ; and sands were deposited at the foot of the cliffs that 

 were later to be transformed through the action of iron salts 

 and iron oolitic carbonates x into red sandstone, such as that 

 of Saint-Remy (Calvados), Segre (Maine-et-Loire) , Nucic 

 (Bohemia), the South of Spain, Saint-Leon (Sardinia), 

 Krivorrog (Southern Russia), and those, somewhat later, 2 

 of Clinton, in New York, and Lake Michigan, and which are 

 accompanied by deposits formed in salt lagoons, such as gypsum 

 and rock-salt, which reappear in all geological periods in places 

 where the sea has receded. 3 



The oceans, however, had extended their domain in both 

 hemispheres towards the equator ; the inter-continental 

 channel or inland sea extended over the north of Africa — 

 which had risen above the water up to that point — as far as 



1 Ordovician. 2 Gothlandian. 3 IX, 490. 



