43G Transactions. — Geology. 



Gasteropoda: Awphibola arellana, Chem. ; Trophon am- 

 higuiis, Phil. ; Troj)lion chioclechnus. Gray ; Trophon 2)lebei2is, 

 Hntton ; Cominella lucida,V\n\.] ClatliurcLla sinclairi, Smith; 

 Tiirhonilla iico.zclanica, Hutton ; Odostovtia lactea, An gas ; 

 Potamoj>ynjiis corolla, Gould; Pautipodiis, Gray; Trochus 

 tiarahis, Q. and G. ; Cantharidns tcnehrosiis, Adams; Mouo- 

 clonta (etliiops, Acmeaflanwiea, Q. and G. ; Conus neozelanicus. 



Lamellibkanx-hiata : Tellhia gIabrella,'Des. ; T. subovata, 

 Sowerby ; Venus sfntcJtbiiryi, Gray ; T'. rnesodesma, Q. and G. ; 

 Tapes intermedia, Q. and G. ; Kellia citrina, Hutton ; Niicula 

 lacunosa, Hutton. 



I l)elieve that all these shells are to be found to-day, if not 

 in the immediate vicinity of Napier, certainly on some portion 

 of the coast-line of New Zealand. They belong to animals 

 which frequent tidal mud-flats like those of our inner harbour, 

 or comparatively shallow waters in quiet bays and coves. The 

 shells named above are found extending from a depth of 112ft. 

 to 175ft. below the present sea-level, and there is every 

 appearance of the animals which once occupied the shells 

 having lived in tlie sands and sand\' clays where the shells are 

 now found. Similar deposits to those in which the shells were 

 found are scattered over the whole of the district included 

 within the artesian basin — varying in thickness, but, on the 

 whole, maintaining their general characteristics. 1 am in- 

 formed by Mr. Hamilton, our secretary, that the animals 

 which occupy shells of the kinds named do not now live at 

 such great depths as those where the shells were found during 

 the process of sinking ; hence it must be inferred either that 

 the animals have modified themselves to altered conditions 

 since the beds overlying the artesian basin were deposited, 

 or that these beds have been deposited on what was a subsiding 

 area. 



Before deciding this question it will be necessary to see 

 what information may be gathered from the rocks surrounding 

 the Heretaunga Plain, which represents the area referred to. 

 At one time, not so long ago considered as a geological period, 

 the Kidnapper beds were united to the Kedcliffe-Taradale 

 beds. Between them that portion of the plain now intervenes 

 which is the very centre of the artesian basin. The Kid- 

 napper beds dip N.W., whilst the Eedcliffe beds dip S.E., 

 so that a syncline, extending for about ten miles, is formed 

 between these two conglomerate and pumice series. The 

 limestone range behind this series runs south-west, forming 

 bold scarps behind Havelock, in the Tukituki Valley. The 

 least observant must have noticed the peculiar slope of these 

 limestones as seen from Napier. These rocks dip N.W., at 

 a fairly high angle under the Heretaunga Plain, the tilt 

 being as if the rocks had suddenl}- snapped away from the 



