Speight. — Redcliff Gully, RaKaia River. 337 



owes its preservation primarily to this position. On both sides of it streams 

 have cut down along the junction of the limestone and the underlying grey- 

 wacke, so that it is partially isolated, but the level of its upper surface is 

 practically that of the saddle, and there is no marked physical feature 

 isolating it in this direction. The front block, whose thickness exceeds 

 150 ft., forms a great cap slightly tilted forward, a position perhaps due 

 to creep of the beds towards the Rakaia. The creek on the western side 

 of this block is known as Packer's Creek, named so from a narrow pack- 

 track leading along its side, w^hile the stream on the eastern side, the larger 

 of the two, is known as Cascade Creek. The latter rises from the saddle 

 itself, and on its steep western bank is a slip in which are exposed all the 

 beds of the series associated with the limestone. Between these two creeks 

 the limestone forms a prominent scarp, extending round in a rude semicircle 

 with its convexity facing the Rakaia. The position of the two creeks has 

 been naturally determined by the line of junction of the limestone with the 

 underlying greywacke, but Cascade Creek is placed on the axis of a small 

 anticline of the folded greywackes. 



Stratigraphy. 



The relative position of the beds occurring in the locality can be best 

 studied in a section that runs in a westerly direction from Cascade Creek, 

 up the slip mentioned previously, over Redcliff Hill, towards Packer's 

 . Creek. The underlying beds, of probable Mesozoic age, in Cascade Creek, 

 consist of slaty shales with bands of greywacke having a northerly strike 

 and a nearly vertical dip (see fig. 1). The an-angement here is distinctly 



Fig. 1. — Section Ai,ONG Line AB, from Packer's Creek to Cascade Creek. 



Length, 1 mile. Direction, N.W. to S.E. 1. Greywackes, &c., varying dip and strike. 

 2. Greensands (darker towards top), 500 ft. 3. Light-coloured sands, with darker 

 glauconitic layers, 150 ft. 4. Marly and sandy beds, with concretionary layers, 

 20 ft. to 30 ft. 5. Limestone, 150 ft., probably more. 6. Sands and shell-beds, 

 over 50 ft. 7. Moraine. 



anticlinal. The direction of the strike is remarkably variable, for on the 

 southern side of the slip the dip is to the south-west, at an angle of 60°. 

 Similar beds also occur in a roche moutonnee in the bed of the river, with 

 a strike a little south of east and an approximately vertical dip. This 

 variation can be seen at times in a very small section, and small faults 

 and marked contortions are frequently visible, emphasizing the intensity 

 of the earth-movements which produced the folding. 



Resting unconformably on these greywackes are the beds with which 

 we are more nearly concerned. The following sequence is exposed in the 

 slip : — 



1 . Greywackes and slaty shales. 



2. Greensands, with an estimated thickness of 500 ft. These beds are 

 light-green below, but become darker in the higher parts. They strike 



