510 THE DISTRIBUTION, ETC., OF ALKALINE ROCKS, 



Antarctica, too, then essentially a land-mass, though the Car- 

 boniferous transgression overlapped considerable areas, has its 

 alkaline rocks scattered widely in its most absolutely unfolded 

 areas. The Dunedin area, the Erebus area, Possession Island, 

 Franklin Island, etc., are placed on the flanks of the Mesozoic 

 Antarctica. 



We see, then, that the existence of alkaline rocks in any area 

 suggests that this area is a remnant of one of the primitive 

 continents, Gondwana-land, Atlantis, Angara, Antarctica or 

 Lemuria. 



Let us now compare the distribution of alkaline rocks with the 

 distribution of land and sea in Jurassic times as represented by 

 Neumayr.* All the North American alkaline rocks lie in his 

 Nearctic continent. All the South American and African 

 occurrences are on or within the boundaries of his Brasilio- 

 Ethiopian continent. Many of the African groups of alkaline 

 rock are situated along the border of his Ethiopian Gulf which 

 probably took its origin in the formation of a senkungsfeld within 

 ancient Gondwana-land, accompanied by marine transgressions 

 due to sedimentation. His Gulf of Queensland was probably 

 formed in a similar way, and all the East Australian and the 

 Otago alkaline rocks occur along its old shore-line. Those of 

 Sumatra and Celebes also lie within Neumayr's Sino-Australian 

 continent. Those of Siberia and Central Asia are situated along 

 its northern coast-line. Those of Scandinavia, Bohemia, and the 

 Ural were islands. Many of the alkaline areas of Central Europe 

 were, however, submerged by a transgression of the sea; the 

 number of islands in this area nevertheless shows that it was a 

 true continental area invaded by transgressions which were 

 perhaps invited by the formation of senkungsfeld-areas. It will 

 be noticed that most of the island-occurrences of alkaline rocks 

 also fall within the continents (figs. 3 and 5), 



On now comparing fig.5 with the distribution of land and sea 

 at the end of the Cretaceous (tig. 4) it is readily seen that the 



* Erdgeschichte, Band ii., p. 263. 



