Art. XXIX —On a New Species of Coral from the Lower Oamaruian Tuffs near Deborah, Oamaru
[Read before the Otago Institute, 5th December, 1916; received by Editors, 30th December, 1916; issued separately, 30th November, 1917.]
Family Oculinidae Milne-Edwards and Haime.
Genus Oculina Lamarck.
Oculina oamaruensis sp. nov.
Corallum dendroid, branches cylindrical or subcylindrical, from 1 cm. to 3 cm. in thickness; calices circular, diameter of calices from 3 mm. to 5 mm.; calices usually from two to three diameters apart, but in a few cases less than one diameter on young branches; in axial direction calices show a tendency to be disposed in regular spirals. The margins of the calices are slightly raised; in some cases they may project as much as 2 mm. The cavity of the calice is shallow Only casts were available for examination, and as the material forming the casts is somewhat coarse in texture the septa are not well preserved, and hence cannot be numbered For the same reason the pali teeth are obscure. The columella appears to be well developed.
Locality.—From bed of calcareous tuff overlying pillow-form basaltic lava at old quarry on north bank of Awamoa Creek, half a mile north of Deborah railway-siding.
Geological Horizon —The calcareous tuff lies about 45 ft below the Oamaru stone It therefore belongs to the Waiarekan stage of the Oamaruian.
Age.—Probably Lower Miocene or Oligocene. This is the first recorded occurrence of the genus Oculina in New Zealand. The Oamaruian species appears to be almost identical with O. mississippiensis (Conrad), 1900, from the Vicksburgian Oligocene of the Lower Mississippi. It may be noted that Oculina mississippiensis (Conrad), 1900 = Madrepora mississippiensis Conrad, 1847; Oculina americana Milne-Edwards and Haime, 1857, and Dendrophyllia mississippiensis Conrad, 1866.