Mr. T. M. Reade on the Drift-deposils of Colwyn Bay. 147 
- The general geological structure was then treated. The south 
island of New Zealand was shown to be traversed from near the 
southern extremity to Tasman’s Bay by a curved anticlinal, convex 
to the westward; and the strata to the east of this axis are thrown 
into secondary folds, which mainly affect the beds older than 
Tertiary. A great north-and-south fault occurs west of the anti- 
clinal. 
The north island is very different. It is traversed by a narrow 
ridge, the country northward of which is broken by three great 
voleanic cones, Mount Egmont, Ruapehu, and Tongariro near the 
centre of the island. The oldest rocks seen south of Cook’s Straits 
are not repeated to the north, and a fault may traverse the Straits. 
The rock-systems up to the Hokanwti inclusive are similar in 
lithological character throughout New Zealand, and appear to have 
been formed on the shore of a continent with large rivers. The 
higher systems, with the exception of a few coral-reef limestones, 
are locally variable and may be considered insular. 
The relative distribution of sedimentary and eruptive rocks was 
briefly noticed, and the occurrence of some useful minerals men- 
tioned. No workable coal is found below the base of the Waipara 
system. 
A description of the different systems, and of the series into 
which they are divided, followed, commencing with the oldest. The 
distribution, lithology, and thickness of each system were noticed 
briefly, and lists of the most important fossils were added. The 
eruptive rocks associated with each system were next noticed in the 
same order ; and the paper concluded with notes on the distribution 
-of volcanic rocks in the north island, on hot springs, and on the 
minerals foind in New Zealand. 
3. “The Drift-deposits of Colwyn Bay.” By T. Mellard Reade, 
Ksq., F.G.S. 
The author, after referring to a former paper (Quart. Journ. 
Geol. Soc. vol. xxxix. p. 111), described the drifts of Colwyn Bay 
as forming cliffs towards the sea, and thinning out inland, forming 
a crescent-shaped deposit, which lies for the most part upon Silurian ~ 
rock of Wenlock age, while the two headlands of Colwyn Head and 
Rhos Point are denuded remnants of Carboniferous Limestone. 
He distinguished three divisions in the drifts:—1. Bluish-grey Till, 
composed of disintegrated Silurian and Carboniferous rocks, and 
full of striated fragments of slaty rock, with few granite boulders ; 
its surface is unevenly denuded. 2. Brown Boulder-clay repre- 
senting the Low-level Boulder-clay and Sands, overlying the former, 
evidently a marine deposit, and containing shell-fragments. To 
this bed the author referred most of the erratics found on the shore, 
which included boulders of Eskdale and Scotch granites; and 
3. Rearranged gravels. The line of demarcation between numbers 
1 and 2 is particularly clear. 
The author considered the Bluish-grey Till to be here, as else- 
