Gilbert. — Geology of Waikato Heads District. 



109 



Minor faulting and some planation, probably by wave-action, occurred, 

 and was followed by the deposition of a dark -greenish sandy bed containing 

 many easily gathered marine fossils. Other similar but less fossiliferous 

 beds follow, being interbedded with thin, hard, closely- jointed, more cal- 

 careous layers, the whole attaining a thickness of 130 ft. to 150 ft.* They 

 are called the " blue marls " or " Cardita beds " by Cox (1877), from the 

 presence in them of " a large Cardita that cannot be distinguished from 

 ' Cardita planicostata ' of Europe [see Hector, 1877. p. viii], and are probably 

 of Lower Eocene age." They are correlated with what has been spoken 

 of earlier in this paper as the tabular limestones of Pa Brown and other 

 localities. 



£?" 



F<>.uit- Strike ra'w ofjv, Hade n'toE- 

 Fig. 9. — Observed section at South Head, Waikawau. 



The exposures of the Notocene beds along Waiwiri Beach show some 

 warping and frequent faulting on a small scale, with possibly a much more 

 powerful fault at a point where the sea-cliffs are temporarily interrupted. 

 (See fig. 10.) 



Fig. 10. — Coast section along Waiwiri Beach (two miles). 



The beds of Koruahine Bluff, at the south end of Waiwiri Beach, which 

 could not be definitely correlated with others either north or south in this 

 section owing to the rapid changes in the facies of the limestones, furnished 

 numerous fossils, among which were abundant echinoids, a few brachiopods, 

 several species of Pecten, and abundant Foraminifera, with occasional sharks' 

 teeth. They are not like the fossils of the " Cardita beds," which are 

 prominent along Waiwiri Beach, but rather resemble those of the shelly 

 bed at the Huruwai Stream and of the tabular limestone at Waikato South 

 Head. These beds probably correlate with the warped and sea-planed 

 beds of the syncline at the base of the Kawa section, for their fossil content 

 is somewhat similar. Thomson has expressed the opinion after examining 

 them that the brachiopods are typically Oamaruian. 



* On revisiting the Waikawau in February of 1920 the writer found an immense 

 slip had recently occurred, obscuring the features of the section here referred to, but 

 facilitating the collection of fossils from a very fossiliferous band higher up the cliff 

 than the rubble-bed. 



