86 Transactions. 
But in saying this he has fallen into an error. The Oamaru stone is 
essentially a polyzoan limestone of high but even grade, the calcium- 
carbonate content seldom falling below 90 per cent. except where mingled 
with voleanie ash. Its distribution shows that it is local, and that it 
accumulated as an off-shore reef or bank where no terrigenous matter was 
being deposited. On the other hand, the Waitaki stone is a low-grade 
arenaceous limestone of extremely variable composition. 
As a rule, the typical Oamaru building-stone is so soft that it can be cut 
with a saw as readily as a log of pinewood. I have examined 110 sections 
of Oamaru stone from Gay's Weston quarry, and forty-two from Totara, 
Teschemaker’s, and Deborah. The Polyzoa range from 28 to 94 per cent., the 
difference from 100 being made up for the most part by Foraminifera with 
some echinoderm plates and rarely shell-fragments. The average sample 
contains about 60 per cent. of Polyzoa and 30 per cent. of Foraminifera. 
Dr. P. Marshall* has described a sample of Oamaru stone as composed 
of Polyzoa, echinoderm plates, and Foraminifera in about equal propor- 
tions. I am satisfied that the sample examined by Dr. Marshall was not 
representative. 
The Waitaki stone, as typically developed near Duntroon, is an impure 
arenaceous limestone intercalated with thin layers of higher-grade lime- 
stone that weather out in the escarpment-faces as prominent bands. The 
analysis} quoted by me, and referred to by Mr. Uttley,f is that of a 
sample collected from several of the highly calcareous bands mentioned 
above. It may be said that these bands taken altogether comprise less 
than 20 per cent. of the Duntroon stone. 
Mr. Uttley§ also refers to the Bortonian stage, the existence of which 
Cainozoic type at Black Point, near Borton’s, in the Waitaki Valley. The 
first collection at this place was made by Mr. McKay|| in 1876, who reported, 
among other forms, the occurrence of Ancyloceras and Scaphites. No 
The fossils from near Windmill Creek and Papakaio were ardh 
referred by me to the Bortonian. The limitations mentioned by Mr. Uttley 
were clearly recognized by me, hence the separate lists of fossils I gave 
іп 1918.4 Till Mr. Uttley is able to furnish some new facts about the 
horizon of the fossils occurring near Windmill Creek and Papakaio we may, 
I think, let the provisional correlation stand. Dr. Thomson has said that 
masses. The fossils from the middle of the boulders are mostly testiferous 
and well preserved. 
In a note to my paper “ On the Age and Relations of the New Zealand 
Coalfields” I stated that I had obtained evidence in north Otago and 
south Canterbury confirming my view that the Pareora beds underlie the 
* Trans. N.Z. Inst., vol. 48, p. 92, 1916. 
T N.Z. Geol. Surv. Bull. No. 20 (n.s.), p. 115, 1918. 
1 Trans. N.Z. Inst., vol. 52, p. 178, 1920. 
$ Loc. cit., pp. 178-79. 
|| Rep. Geol. Explor. during 1876-7 7, p. 52, 1887. 
© N.Z. Geol. Surv. Bull. No. 20 (n.s.), pp. 34, 35, 1918. 
