Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/71

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GEOLOGICAL ARGUMENTS
47

only occur in the province of Minas Geraes in Brazil and in South Africa only north of the Orange River. But, more clearly than in these rare occurrences of diamonds, the agreement is shown in the distribution of the kimberlite matrix. This has also been recognized in dykes in the province of Rio de Janeiro. “Like the kimberlite rocks near the west coast of South Africa, those known from Brazil practically all belong to the basaltic varieties poor in mica.”

But Brouwer also emphasizes the fact that the sedimentary rocks on both sides show a great correspondence. “The similarity between some groups of sedimentary rocks on both sides of the Atlantic is equally remarkable. We need only mention the South African Karoo System and the Santa Catharina System of Brazil. The Orleans conglomerate in Santa Catharina and Rio Grande do Sul corresponds to the Dwyka conglomerate of South Africa, and in both continents the uppermost portions are formed by an already well-known thick series of volcanic rocks, as those of the Drakensberg in Cape Colony and those of the Serra Geral in Rio Grande do Sul.”

According to du Toit,[1] it even appears as if the Permo-Carboniferous erratic material in South America is partly derived from Africa. “The Southern Brazilian tillite was, according to Coleman, derived from a sheet probably having its centre to the south-east,[2] off the present coast-line. Both he and Woodworth also record certain erratics of a peculiar quartzite or grit with banded jasper pebbles, which from their accounts are just like those collected by the Transvaal ice from the ranges of Matsap beds in Griqualand

  1. Alex. L. du Toit, “The Carboniferous Glaciation of South Africa,” Trans. Geol. Soc. S. Africa, 24, pp. 188–227, 1921.
  2. This is written, by an oversight, as “south-west” in the original.