Note 24 — Chapter IV · ON THE FORMATIONS OF THE PAMPAS.

I may add, that there are nearly similar superficial calcareous beds at King George’s Sound in Australia; and these undoubtedly have been formed by the disintegration of marine remains (see “Volcanic Islands,” etc., p. 144). There is, however, something very remarkable in the frequency of superficial, thin beds of earthy calcareous matter, in districts where the surrounding rocks are not calcareous. Major Charters, in a Paper read before the Geographical Society (April 13th, 1840, and abstracted in the Athenæum, p. 317), states that this is the case in parts of Mexico, and that he has observed similar appearances in many parts of South Africa. The circumstance of the uppermost stratum round the ragged Sierra Ventana, consisting of calcareous or marly matter, without any covering of alluvial matter, strikes me as very singular, in whatever manner we view the deposition and elevation of the Pampean formation.