414 Transactions. — Geology. 



gasworks ; and they are in the Tutaekuri as low down as the 

 mouth of the New Cut. 



These rough notes are taken mainly from the point of 

 view of a lover of shells and plants ; but it would seem that 

 this area would afford a most interesting harvest to those 

 interested in crustacean and insect life, the crustacean life of 

 the salt and brackish water giving place to the insect-life of 

 the fresh, and of the insects themselves the littoral giving 

 place to the inland species. The fauna of the New Cut gives 

 a fair illustration of this. Where this canal joins the channel 

 just below the recreation - ground the hand-net brings up 

 small crabs, shrimps, sand- hoppers, and a crustacean very 

 like a woodlouse with swimming-lobes to its tail-segments. 

 Following up the Cut with the net, the crabs soon disappear, 

 then the water-slater; sand-hoppers and shrimps become 

 scarce ; and as one nears the Tutaekuri the larval forms of 

 insects come up in the net — the hideous masked nymphs of 

 a dragon-fly, and lesser relatives, the sand and horny tubes of 

 caddis-worms, with fresh -water shells and drowned land- 

 shells, and the seeds of many inland plants, just such a haul 

 as one may take from a mat of watercress in one of our up- 

 land streams. 



Akt. XXXIX. — On the Volcanic Grits and Ash-beds in the 



Waitemata Series. 



By B. K. Mulgan, M.A. 



[Read before the Auckland Institute, 5th August, 1901.] 



Plates XXII- XXVI. 



Section I. — Introduction. 



The object of this paper is to describe a deposit of volcanic 

 grit which occurs in a Tertiary formation known as the 

 " Waitemata series." This series, of Bower Miocene age, 

 is developed from the Auckland isthmus northwards for 

 upwards of twenty miles, and stretches completely across 

 the Island. The volcanic grits outcrop for the most part 

 along the shore-line, and lie conformably between the sedi- 

 mentary strata. To trace individual beds in this series is 

 a matter of great difficulty, as these not only thin out 

 and disappear, but are in places considerably disturbed 

 and faulted. Fossils, moreover, occur but sparingly. The 

 grits, however, are amongst the most distinctive beds, and 

 in nearly all cases are fossiliferous. For these reasons they 



