Мовросн AND Frintay.—Land Mollusca in Recent Sea-beach Deposit. 131 
Авт. 12.— The Occurrence of Land Mollusca in a Recent Sea-beach 
Deposit. 
By В. Мовросн and Н. I. Finuay, M.Sc. 
{Read before the Otago Institute, 8th November, 1921 ; received by Editor, 5th December, 
1921; issued separately, 12th February, 1923.) 
Plate 17. 
During the early part of this year, one of us (Finlay), when examining 
the shore-line near the mouth of the Akatoa Creek, made the discovery 
of a small beach deposit exceedingly rich in land-shells. 
Records of our land Mollusca occurring in the Recent rocks are ver 
rare, and the same may be said of their occurrence subfossil; no con- 
siderable assembly of species has been found, nor an abundance of any 
single species. It is therefore of particular interest to find, on the highest 
margin of the strand, no less than ten species of land Mollusca, including 
an undescribed species of Ptychodon. The majority of the species are in 
and, from the freshness of their 
colours, give the false impression that they had not been deposited for 
more than a few months. The bed in which they occur has n i 
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Akatoa Creek opens on to the coast some five or six miles south 
of the Taieri River, and the deposit in which the shells occur is north of 
this creek some 20 or 30 chains, situated in one of the sinuosities of the 
coastal line, and backed by low hillocks. The bed occupies the highest 
margin of the strand, as illustrated (Plate 17, fig. 1). It has a length of 
about 130 ft. and a greatest thickness of approximately 3 ft., thinning out 
to the end most distant from the Akatoa Creek. Mr. Agnew, who has 
oceupied the adjoining lands for the past thirteen years, states that the 
d was in existence prior to his arrival, that he has made constant use 
of it for poultry-grit, and that he has not observed any marked differences 
in its extent during that period. There can be no doubt that the bed 
has suffered from tides and storms, but, from the fact that it has in a 
measure survived the storms of perhaps a score of years, its remnant may 
be regarded as fairly secure against the ravages of the sea. 
he bed consists of a coarse quartz sand, a considerable amount of 
dark loamy earth, and a few stones, the latter with sharp fractures an 
of scrub in the numerous small gullies, there is now no native bush of any 
extent within two or three miles of the coast. 
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