•382 Transactions. — Geology. 



The remains are too fragmentary even for generic identifi- 

 cation. 



The Sinriferina beds are underlain in descending order by 

 sandstones, often coarse and gritty, and sandstones and clay- 

 stones alternating in thin laminae. The latter form the' 

 "Nuggets" and the promontory on which the lighthouse 

 stands. Here the beds strike W.N.W. - E.S.E., and dip 

 S.S.W. at very high angles, at places becoming nearly vertical. 



On the islet, in the centre of the Nugget group of rocks, 

 the strata are sharply folded and pinched. 



In the road-cutting leading to the lighthouse, at a point 

 about 15 chains beyond the keeper's house, the strike of the 

 beds is between E. and E.S.E., and the dip about S.S.W. at 

 ■an angle of 70°. Here the sandstones are interbedded with 

 beds of soft shaly claystone containing numerous plant- 

 remains, but too broken and fragmentary to be identified. 

 The plant beds are about 850 ft. below Spiriferina beds. 



Sliatv Bay Section. 



From the head of Shaw Bay to the headland separating 

 that bay from Sandy Bay, a distance of half a mile, the strike 

 of the beds is W.N.W. - E.S.E. almost without variation, 

 and the dip continuously S.S.W. at very high angles, gene- 

 rally between 75° and 85°. 



The coast-line trends almost at right angles to the strike 



of the beds, and, the angle of dip being high, bed succeeds 



bed with wonderful regularity, appearing in the sea-cliffs 



which enclose the bay as clearly defined as books standing 



■on a shelf. 



There is exposed along this line of section a thickness of 

 fully 2,500 ft. of strata in one continuous sequence, forming 

 the most complete assemblage of Lower Mesozoic rocks in 

 New Zealand, singularly free from faults or complicated fold- 

 ings that might cause obscurity or lead to doubtful interpre- 

 tation. Furthermore, the fossiliferous zones are numerous, 

 and so distinctive as to be easily recognised. 



Beginning at the north end of Shaw Bay, the beds ex- 

 posed along this line of section and their approximate thick- 

 ness are as follows in ascending order : — 



1. Thin laminated claystones and sandstones with plant- 



remains, probably 200 ft. thick. 



2. Indurated sandstones and greywacke, 150 ft. 



3. Spiriferina beds — dark- blue claystones, 100 ft. 



4. Porphyrite dyke. 



5. Greywacke. 



6. Halobia beds about 210 ft. thick — crumbling claystones 



containing Halobia loinmclt, Wissm., lietzia, Ejnthi/- 

 ris. Seen in road-cutting descending to the bay. 



