Keywords: South African Geology - Schwarz - 1912 Fig 8.png Holtenia carpenteri Wyville Thomson a siliceous sponge the spicules of which go to form the flint nodules in chalk and the bands of chert in dolomite b Pentacrinus wyville-thomsoni Jeffreys a crinoid that yields calcium carbonate to the sediments c Globiyerina bulloides d'Orbigny highly magnified The dead shells are shown as they fall to the bottom of the sea d Coccosphere made of coccoliths very highly magnified c and d are free-swimming organisms that yield the greater amount of calcareous matter to the deep sea oozes which consolidate as chalk From Professor Wyville Thomson's Depths of the Sea Macmillan Co Page 49 1912 File South African Geology - Schwarz - 1912 djvu Schwarz Ernest Hubert Lewis 1873-1928 other versions PD-old-70-1923 South African geology book |