1919.] Wild and Speight. — Limestones of Canterbury. 183 
bone occur in the nodules and in the matrix associated with them, and 
indicate a possible source of the phosphatic material. As a general rule, 
however, it may be regarded as derived from the underlying limestone 
by a process of differential solution of the carbonate and a consequent 
concentration of the more insoluble phosphate in the upper layer of the 
limestone and in the beds immediately overlying it. In order to give an 
accurate conspectus of the circumstances of the case, detailed descriptions 
are given of sections at Kaikoura, Amuri Bluff, Port Robinson, and Weka 
Pass. It will be recognized immediately that the layer mentioned is of 
wide distribution, but that its comparatively narrow width and difficulty 
of access militate strongly against its use as a commercial supplier of 
phosphate rock. 
Kaikoura . — The phosphate horizon is exposed at several places in this 
locality, but the best sections are to be seen on the shore platform near 
the Maori village on the south side of the peninsula, and on its south-east 
corner near Atiu Point. The following description fits both places :— 
(1.) Amuri limestone, at the base, followed by— 
(2.) 8 in. to 10 in. showing borings filled with greensand, and con¬ 
taining detached fragments of greensand and occasional nodules. 
(3.) Nodular layer, 8 in. to 10 in. thick, with green and black nodules 
in a matrix of greensand, the nodules forming about 50 per cent, 
of the material. 
(4.) Glauconitic limestone with alternating layers, more or less glauco¬ 
nitic, the limestone sometimes with flints, and finally passing 
up into— 
(5.) Amuri limestone, exhibiting its typical characters as regards texture, 
colour, jointing, and presence of flints. 
This layer occurs wherever the proper horizon is exposed round the 
peninsula, but never in such a situation that it could be stripped away 
readily. The beds associated with it either exhibit a steep inclination 
or, when flat, are covered by a great thickness of overburden, so that the 
exploitation of the lajmr would necessitate actual mining operations. The 
layer is too thin to be worked economically at present prices in such a 
way, although it is possible that if the shortage became acute its working 
might be considered, especially as the deposits are within a very short 
distance from a tolerable port, access from which is easy. 
Amuri Bluff ,—The nodular layer is exposed in places on the cliffs 
between the mouths of the Oaro and Mikonui Creeks, but the best 
exposure of all is on the raised shore platform at the base of the cliffs on 
the south side of the bluff. The following section occurs here :— 
(1.) Amuri limestone. 
(2.) Layer, 4 ft. thick, completely bored, with tubes filled with 
calcareous greensand, the phenomenon being progressively more 
marked as the upper surface is reached. 
(3.) Layer, 2 ft. thick, where greensand increases in importance and 
nodules occur, the true nodular layer in which they are concen¬ 
trated being from 10 in. to 12 in. thick; occasional bones 
(? whale-bones) and sharks’ teeth occur in this layer. 
(4.) Greensand layer, about 3 ft., passing up into limestone, with 
sporadic nodules. 
(5.) Amuri limestone, differing in appearance from the typical rock 
and resembling more the Weka Pass stone. 
