GEOLOGY. 
109 
limestone bands are only one to one and a-half feet thick, whilst 
the intervening chalk marl strata have an average breadth of six 
feet; but in the next 130 feet the bands become broader and the 
chalk marl less wide, the limestone constituting below these the 
whole rock. The limestone too becomes more sandy, and is some¬ 
times charged with small fragments of coal, probably derived from 
the detritus of the Davy mountains. The same fossils as before 
enumerated continue to be numerous, as well as the remains of 
a crustacean (a crab), pieces ot coral, a large Lima, a large fossil 
allied to Exogyra, another allied to Crania, and numerous Serpulae. 
Ibis formation, which ceases when the Davy mountains, upon 
which it lies unconformably, approach the coast, again appears at 
the Punakaiki clifts. Here it consists of greensands full of glau¬ 
conitic grains, but without any signs of stratification, the colours, 
greenish and darkish yellow, being the only lines of demarcation 
between the various deposits. These greensands are from 100 to 
120 feet thick, and are underlaid by arenaceous flaggy limestones, 
with a regular strike from west-north-west to east-south-east, and 
a dip of 17 degrees towards the west-south-west. Below these 
again, on the southern bank of the Pororari, a white crystalline 
tabular limestone appears, consisting of small fragments of shells, 
corals, and Foraminiferae, with glauconitic grains, forming castle¬ 
like walls, arches, and towers, and presenting magnificent scenery. 
Below these we meet with dark marls, often very argillaceous, 
between which small flaggy beds of the above-described limestone 
lie. Here I first found large fossil oysters and Scalarise, as well 
as the greater part of the fossils before enumerated. 
These cretaceous beds continue for five miles, but for a long 
distance I had no opportunity of examining the rocks near the 
sea, having to scramble through the dense vegetation at the sum¬ 
mit of the perpendicular cliffs. In the gullies, however, although 
I observed that nearly the same strike and dip continued, the 
underlying strata were sometimes of a nearly earthy texture, in 
which concretions of chalcedony were imbedded; in other places 
they were more argillaceous, and of a yellowish colour, 'with con¬ 
cretions of iron pyrites, but at intervals of fifteen to twenty feet 
small layers of white crystalline limestone occurred. Scalariae 
here abounded, and I observed that the exuviae were most 
numerous where the change took place from crystalline limestone 
to clay marl, the upper surface of the clay marl bed being literally 
strewed with fossil shells, amongst which large pectens pre¬ 
dominated. 
Half a mile north of the Mico Cliffs the granite begins, upon 
w r hich the above formation, which is at least 1,500 ieet thick, 
rests. As these beds lie everywhere along the West Coast 
directly upon the granite, we may infer that the protrusion of the 
latter occurred either during the cretaceous period (all the older 
cretaceous strata with belemnites and ammonites ol the Kawbia 
