596 Transetciions. 



2. A New Fossil Mactra. 

 Mactra chrydaea n. sp. Plate XXXI. 



Shell small, ovate-trigonal, somewhat inflated, not gaping, with rather 

 coarse concentric sculpture, equivalve, somewhat inequilateral, the anterior 

 end a little shorter. Beaks slightly anterior, close together, prosogyrate, 

 incurved, pointed. Anterior end convex, the dorsal margin lightly rounded, 

 oblique. Posterior end subtruncated, very little arched, the dorsal margin 

 convex and rather rapidly descending. Basal margin lightly convex, 

 forming an obtuse angle with the posterior margin. Posterior area but ill 

 defined, an obtuse keel descending from the beak to the postero-ventral 

 angle. Sculpture consisting of vv-ell-marked concentric ridges, usually with 

 deep sulci towards the base ; under a lens rather distant radiate striae can 

 be seen, which are more distinct on the median part of the valves. 



None of my specimens shows the interior of the valves, and the matrix 

 is too hard to be removed without breaking the valves. 



Length, 23 mm. ; height, 19 mm.. ; diameter, 15 mm. (specimen figured). 

 Length, 28 mm. ; height, 22 mm. ; diameter, 19 mm. (larger shell). 



Type in my collection. 



Loc. — It occurs in great abundance in the upper horizon of the Lower 

 Pliocene blue sandy clays on the North Island Trunk Line, between Mataroa 

 and Turanga-a-rere (J. Park). 



Remarks. — This species is quite distinct from all the Recent and fossil 

 New Zealand species of the genus. I wish to thank Professor J. Park for 

 the specimens and the oppoitunity of describing them. The photo w^as 

 most kindly provided by Mr. A. Hamilton, Director of the Dominion 

 Museum . 



Art. LIII. — Maori Rock-engravings in the Kaipara District. 



By R. BuDDLE. 



[Bead before the Auckland Institute, 22nd November, 1910.] 



Plate XXXII. 



It is with no little diffidence that, upon the suggestion of Mr. Cheeseman, 



of the Auckland Museum, I venture to submit to the Institute this short 



account of some rock-carvings which I accidentally discovered on an ancient 



pa near the small settlement of Haranui, in the Parkhurst district, Kaipara. 



The pa is within a mile of the famous old pa of Otakaiiini. It is a fine 

 one, situated on a ridge, with the mud-fiats of the harbour on one side 

 and a swamp on the other. The whole ridge shows (as is so often the case) 

 evidences of excavations, ditches, &c., while the main part, which is raised 

 above the general level, is cut oft" by a deep ditch, and has an outwork at 

 one corner which commands the most accessible flanks. 



On the main terraces are several rectangular excavations which indicate 

 that they were the sites of wharepuni, or " warm houses." It is on the side 

 of one of these excavations that the designs are engraved in the soft sand- 

 stone. As there is a small modern cemetery just above, I was at first in- 

 clined to believe that they were of modern origin — that they were perhaps 

 the work of some Maoris Avho had com.e there for the purpose of digging a 

 grave ; but, as the Natives whom I questioned pointed out, men engaged 

 in such work were not likelv to linger in the vicinitv of a cemetery to waste 



