The chief groups of animals and plants forming such limestone rocks are:-- (a) _FORAMINIFERA._--Example. Foraminiferal limestone as the Nummulitic limestone of the Pyramids of Egypt, or the _Lepidocyclina_ limestone of Batesford, near Geelong, Victoria (Fig. 43). [Illustration: =Fig. 43.= =Limestone composed of Polyzoa and Foraminifera (Lepidocyclina).= × 6. Cainozoic (Janjukian). Batesford, near Geelong, Victoria. (_F.C. Coll._) ] (b) _CORALS._--Ex. "Madrepore limestone," or Devonian marble, with _Pachypora_. Also the Lilydale limestone, with _Favosites_, of Silurian age, Victoria (Fig. 44). [Illustration: =Fig. 44.--A Fossil Coral (Favosites grandipora).= 2/3 nat. size. From the Silurian of Lilydale, Victoria. (_F.C. Coll._). ] [Illustration: =Fig. 45.--Polished Slab of Marble formed of Joints of Crinoids.= About 2/3 nat. size. Silurian. Toongabbie, Gippsland, Victoria. (_Nat. Mus. Coll._) ] (c) _STONE-LILIES._--Ex. Crinoidal or Entrochial limestone, Silurian, Toongabbie, Victoria (Fig. 45). Also the Carboniferous or Mountain limestone, Derbyshire, England. (d) _WORM-TUBES.-_-Ex. Serpulite limestone of Hanover, Germany. _Ditrupa_ limestone of Torquay and Wormbete Creek, Victoria. (e) _POLYZOA._---Ex. Polyzoal limestone, as the so-called Coralline Crag of Suffolk, England; and the Polyzoal Rock of Mount Gambier, S. Australia. (f) _BRACHIOPODA._--Ex. Brachiopod limestone of Silurian age, Dudley, England. _Orthis_ limestone of Cambrian age, Dolodrook River, N. E. Gippsland. (g) _MOLLUSCA._--Ex. Shell limestone, as the _Turritella_ bed of Table Cape, Tasmania, and of Camperdown, Victoria (Fig. 46), or the Purbeck Marble of Swanage, Dorset, England. [Illustration: =Fig. 46.--Turritella Limestone.= (T. acricula, Tate); 3/4 nat. size. Cainozoic. Lake Bullen Merri, near Camperdown, Victoria.] [Illustration: =Fig. 47.--Limestone composed of the Valves of an Ostracod (Cypridea).= Upper Jurassic. × 9. Swanage, Dorset, England.] (h) _OSTRACODA._--Ex. Cypridiferous limestone, formed of the minute valves of the bivalved ostracoda, as that of Durlston, Dorset, England (Fig. 47). (i) _CADDIS FLY LARVAE._--Ex. Indusial limestone, formed of tubular cases constructed by the larvae of the Caddis fly (_Phryganea_). Occurs at Durckheim, Rhine District, Germany. (j) _RED SEAWEEDS._--Ex. Nullipore limestone, formed by the stony thallus (frond) of the calcareous sea-weed _Lithothamnion_, as in the Leithakalk, a common building stone of Vienna. (k) _GREEN SEAWEEDS._--Ex. _Halimeda_ limestone, forming large masses of rock in the late Cainozoic reefs of the New Hebrides (Fig. 48). (l) (?) _BLUE-GREEN SEAWEEDS._--Ex. _Girvanella_ limestone, forming the Peagrit of Jurassic age, of Gloucester, England. Section IV.--CARBONACEOUS and MISCELLANEOUS ROCKS.