418 



Transactions. — Geology. 



Tamaki Point, a similar band appears, almost identical in 

 texture and mineral contents with that outcropping at Parnell. 

 (In point of fact, the only difference is that the St. Helier's 

 Bay beds are slightly coarser at the base.) To the west it 

 appears in St. George's Bay, dipping east at an angle of 30°, 

 the connection between the two bands being shown in section 

 in fig. 1. Between the two exposures the sedimentary strata 

 are much disturbed, in places being thrown on end. There 

 seems to be little doubt that to the same band of grit can be 

 traced the exposures at St. George's Bay, Judge's Bay, St. 

 Helier's Point, and Tamaki Point. 



Fig. 1. 



P' Resolution 



Judge's Bay 



S c George'j 

 Bay 



Plan. D. Section through AB, showing connection between outorops 

 of volcanic grit at Judge's and St. George's Bays, known as the " Par- 

 nell grit": 1. Volcanic grit. 2. Sandstones and shales. 



Following the shores of the harbour westward, a similar 

 band of volcanic grit is met with about a mile and a half fur- 

 ther on below Point Acheron. The exposure occurs on the 

 shore-line, and the band appears to dip west at an angle of 

 10° ; but since it cannot be traced into the cliff it is impos- 

 sible to estimate its thickness or be sure of its dip. Half a 

 mile beyond this, near Point Erin, a similar band, 12 ft. in 

 thickness, outcrops in the cliff and dips west at an angle of 

 17°. A few hundred yards further on, at Shelly Beach Point, 

 it again appears, lying almost vertically between the other 

 sedimentary strata. (See fig. 2.) 



The band of grit strikes north from Shelly Beach Point 

 and sends out a long reef into the harbour in that direction. 

 As in the case of the Parnell grit, the strata between the out- 

 crops are disturbed and faulted. The grit in this exposure is 

 composed of volcanic material similar to that comprising the 

 Parnell ash-beds. 



