Thomson. — Geology of Middle Waipara and Weka Pass District. 347 



Bohy's Creek. — The " saurian beds " and Waipara greensands of the 

 Boby's Creek watershed closely resemble those in the Waipara River. The 

 Ostrea bed is followed down-stream by sandstones forming grey to light- 

 yellow cliffs, and becoming more argillaceous when traced upwards, finally 

 passing into grey sandy mudstones with marked yellow efflorescence. Saurian 

 concretions commence a very short distance above the oyster-bed, but 

 rarely exceed 4 ft. in diameter. Near the top these grey mudstones are 

 notably streaky and inclining to be purple, and they are succeeded by a 

 bed of loose sand about 20 ft. thick, which in turn is followed by similar 

 streaky mudstones rapidly passing up into purple micaceous mudstones, 

 which here abut against the fault. The higher beds appear on the high 

 terrace on the south bank and up the most easterly tributary on this side, 

 and consist of the concretionary greensands, the still higher laeds not being 

 exposed. The thicknesses of the above beds cannot be accurately esti- 

 mated, as the bedding-planes are not well expressed, and the creek runs 

 obliquely to the strike. In the upper part of Bell's Creek, besides the 

 above rocks a small exposure of the upper Waipara greensands occurs. 

 The whole series should be exposed in Boby's Creek above the waterfall, 

 but I have not studied it there. 



The following species of saurians, collected by Holmes, Travers, McKay, 

 and von Haast, have been determined from the " saurian beds " of Boby's 

 Creek : Cimoliosaurus australis (Owen), C. haasti (Hector), and C. caudalis 

 Hutt.. From Hector's collection of 1867, Chapman (1918) identified the 

 following ^fish-remains : Teeth of Scapanorhynchus suhulatus (Ag.) and of 

 Odontaspis incurva (Davis), and vertebrae of Lamna (?). Presumably these 

 are from the " saurian beds." 



Weha Creek. — The Ostrea beds are followed by loose sands of consider- 

 able thickness, which become more sulphurous and argillaceous in their 

 upper part. The succeeding mudstones are harder than in the Waipara 

 River, and in places are almost, flinty and contain impure flint nodules 

 a few inches in diameter. They are slightly micaceous, and are pale 

 lilac on Aveathered surfaces, with rusty joint- planes and an occasional yellow 

 efflorescence. These flinty mudstones present a great resemblance to 

 Clarentian flinty mudstones in the Kekerangu and Benmore areas both 

 in texture and colour. In their upper part they become less hard, and 

 greyer in colour. No saurian concretions are seen either in situ or in the 

 stream-gravels lower, down, and are probably absent in this locality. The 

 succeeding beds (Waipara greensands) are not here exposed, owing to a slip 

 of Aniuri limestone covering them. 



In the northern tributary of Weka Creek rising near Waikare the hard 

 bands of the Waipara greensands crop out at a number of points or form 

 sheadings on the lower hills below the high cuesta of Amuri limestone and 

 Weka Pass stone, and cross over into the Waikare watershed at the western 

 end of Waikare Township. Thence the Waipara greensands extend as a 

 narrow strip to the east between the township and the hills, but are partly 

 covered by surface deposits of soft limestone and sands. Loose greensands 

 are exposed in the excavations for the Waikare hospital site. 



Weka Pass- Waikare Saddle. — Between the Waikare flat^ and the upper 

 ])art of the Weka Pass the upper Piripauan beds are disposed in a flatly- 

 dipping anticline around the western end of the ridge of pre-Nptocene rocks 

 which lies to the south of the Waikare Stream, and are exposed in the 

 railway-cutting on the saddle near the 47 -mile peg from Chrktchurch. The 

 sides of this cutting are now considerably slipped and Mavily grassed. 

 Hutton (1885), who had an opportunity of examining this section soon after 



