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Neoretzia sp. (MPC1_390) in a coarse gritstone from scree in Highfield Farm.
Two specimens of Retziidae from the 88 Valley on Highfield Farm: MPC1_388 (left) tentatively assigned to Neoretzia. sp. and MPC1_389 (right) tentatively assigned to Retzia sp.
Description of Retzia schwageri (Trechmann 1918): Shell considerably longer than it is wide, beak prominent and pointed, lateral margins gently rounded, anterior margin rounded. The dorsal valve has a median rib, which is rather less prominent than the ribs on each side of it. There are seven rounded lateral ribs on each side of the median one; the last five of these are distinctly curved outwards, and all of them extend to the beak. The ventral valve has a median furrow no deeper than the next lateral furrows and seven lateral ribs. Length=14ram.; width--ll mm. Further Reading: Trechmann, C.T. 1917 The Trias of New Zealand. Quarterly Journal of the Geological Society 291, 165-246 (+ 10 plates). |
Retziidae
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