1921 .] 
Departmental Reports. 
29 
to rise from the present flood-plain of the stream to a terrace 50 ft. higher, 
the following forms were obtained :— 
Chione sp. 
*Dentalium ecostatum T. W. Kirk. 
*Dentalium nanurn Hutt. 
*Dentalium zelandicum Sow. 
*Drillia chordata Sut. 
*Drillia laevis (Hutt.). 
*Malletia australis (Q. k G.). 
Pecten delicatulus Hutt. 
Pecten sp. 
Siphonalia elegans Sut. 
Siphonalia sp. 
*Turritella symmetrica Hutt. 
*Venericardia lutea (Hutt.). 
*Zenatia acinaces (Q. & G.). 
The most abundant fossil is the Turritella, which also occurs plentifully 
in the sandstone exposed in Swamp Creek, a mile to the south-east, and at 
Port Robinson. From the soft sandstone of the last-mentioned locality, 
called by Haast the Turritella beds, a small collection was made which 
included about half of the forms named above and none specifically different. 
Of those specifically named in both collections all except Pecten delicatulus 
and Siphonalia elegans occur in the Wanganui bedsf and aie also living 
forms. 
Economic Geology. 
From time to time the Government Analyst has received small samples 
of petroleum from the Cheviot district. The localities where oil occurs 
were visited by the writer in November, 1919. 
A crush-zone striking north-north-east traverses the greywackes about 
two miles east of Cheviot. At three points along it, where shallow holes 
had been excavated in the soft pug, the odour of kerosene was plainly 
evident, although the water filling the holes showed no trace of oil-film. 
Immediately to the west of this crush-zone the younger rocks form a steep 
escarpment capped with limestone, and the oil in the pug may well have 
been derived from these younger beds. Three-quarters of a mile from 
the mouth of Jed Stream, where the contact between the greywackes and 
the overlying beds is well exposed, a faint odour of kerosene was noticed 
in the pug of a shatter-zone in the older rocks. A few chains down-stream, 
where the steam flows over the younger strata, bubbles of gas rise through 
the sands and gravels of the stream-bed. The gas, which escapes only 
in small quantity, smells decidedly of sulphuretted hydrogen, and a dark 
dirty-green discoloration round the vent was no doubt due to the decom¬ 
position of this gas. A sample of the emanation from this spring was found 
by the Dominion Analyst to consist of— 
Carbon dioxide (C0 2 ) . . . . . . .. 0-60 
Methane (CH 4 ).. .. .. .. .. 65*15 
Oxygen (0) . . . . . . . . ,. 2*45 
Nitrogen (N) . . .. . . .. . . 31*80 
100*00 
Other points of emanation, also marked by green discolorations of the 
surrounding gravel and sand, were observed in the creek-bed 30 chains 
down-stream. 
The odour of kerosene in the instances mentioned above was associated 
with crush-zones traversing the old rocks of the district, although in each 
t P. Marshall and R. Murdoch, The Tertiary Rocks near Wanganui, Trans. N.Z. 
Inst., vol. 52, pp. 115-28, 1920. 
