392 Transactions. — Geology. 



abundant the adjoining beds are covered with an efflorescence 

 of sulphur. 



About lOt't. from the foot of the chff there is a very 

 characteristic band of gritty sandstone, speckled pretty evenly 

 with small fragments of grey clay. This, or a similar bed, is 

 seen at the top of the cliffs leading round the point from 

 Mechanics" Bay to St. George's Bay, and again near the top of 

 the cliffs behind the Calliope Dock. 



The character of the sediments, together with their fossil 

 contents, leave little room for doubt that the beds composing 

 the Waitemata series are mostly of estuarine origin ; while 

 the marine forms in the Motutapu beds and Parnell grit, and 

 in the calcareous cornstones at Orakei Bay, St. George's Bay, 

 and Onehunga, point to several periods during which the 

 conditions of deposition were truly marine. 



Around Auckland there is no stratigraphical evidence to 

 fix the age of this series. On the isthmus, and at the North 

 Shore, they are overlain unconformably by stratified tuffs, 

 solid lava-flows, and scoria-beds of probably Post-pliocene 

 age ; while at Motutapu Island they rest on, or, rather, lap on 

 to, a highly-denuded rocky surface of the basement-rock of the 

 district, of Palaeozoic age, consisting of indurated sandstones 

 and slaty shales. 



The late Dr. von Hochstetter, in his lecture to the Auck- 

 land Institute, 24th June, 1859, speaking of these beds, says, 

 " The horizontal beds of sandstone and marls which form the 

 cliffs of the Waitemata, and extend in a northerly direction to 

 Kawau, belong to a newer Tertiary formation, and, instead of 

 coal, have only thin layers of lignite. A characteristic feature 

 of this Auckland Tertiary formation is the existence of beds of 

 volcanic ashes, which are here and there interstratified with 

 the ordinary Tertiary layers."''' Subsequently he places the 

 Waitemata series with the Aotea series, both being considered 

 as Older Miocene. f 



Professor Hutton, in a paper read before the Auckland 

 Institute in 1870, showed that this series could be traced 

 eastward beyond Tamaki and Howick to Turanga Creek, 

 where, he says, " it rests unconformably on a dark-green or 

 bluish sandstone, generally showing a concretionary struc- 

 ture." I 



In 1879 Mr. S. H. Cox, late Assistant Geologist, examined 

 the country from Auckland northward to Cape Eodney and 

 the Kaipara. During this survey I accompanied him as his 

 assistant, and at Komiti Peninsula, opposite Batley, we made 



* " Geology of New Zealand," Hochstetter, 1864, p. 26. 

 t " Reise der ' Novara :' Geology," i., p. 34. 

 + " Trans. N.Z. Inst.," vol. xvii,, p. 307. 



