51 



.springs, with good water, and maintains a permanent flow. 

 The water is precipitated from a hanging valley, 80 ft. in 

 height, no doubt occasioned by the cutting back of the- cliffs 

 by the sea; the first 20 ft. of the fall is vertical and the 

 lower 60 ft. is encumbered by large masses of rock that have 

 accumulated at a sharp angle of its descent. 



A little to the south of Waterfall Creek (No. 2), the 

 Eocene limestones reappear, both on the beach and in the 

 •eliffs, the coastline at this spot having a more westerly exten- 

 sion, which probably accounts for the reappearance of the 

 beds. These exhibit a high angle of dip, ranging from 40° 

 to 90°, and in one instance, at least, to a distinct overfold. 

 In the sea cliffs, the Eocene beds, to a height of 100 ft., form 

 -a thick veneer, resting on the Cambrian rocks, and dip at 

 ^n angle of 80°. The dip, however, is not in the form of a 

 straight line, but a curve, in which the upper part dips at a 

 lower angle than those portions of the fold that are a.t sea- 

 level. This gives the beds the appearance of a monoclinal 

 fold, of which only the western limb or septum has been pre- 

 served, for the Eocenes run out, easterly, where the ground 

 rises at the back of the cliffs. 



The beach at this spot is composed of a number of 

 parallel ridges caused by the truncation of the beds 

 at sea-level. Some of these ridges are very strong and 

 look like masonry. Where the stone has been of superior 

 hardness, sea-stacks, of about 8 ft. in height, have resisted 

 the action of the waves and give evidence as to the dip of the 

 fbeds a short distance in advance of the cliffs. Some instruc- 

 tive sections are thereby obtained. Several of the stacks 

 show the Eocene limestones in a vertical position, and, in one 

 case, the beds are reversed (plate xviii.). In another stack 

 there are several sharp folds, which, in a zone of about a 

 foot in thickness, exhibit herring-bone structure (plate xvii.). 

 As a rule the beds are not greatly disturbed, other than by 

 the main movement of downthrow, but in a few places, especi- 

 ally near the base of the beds, there are evidences of shatter 

 and some mixing up of the beds. 



In one case, seen in the sea cliffs towards the southern 

 end of the section, a very distinct shear plane with over- 

 thrust has been developed. The shear plane forms a distinct 

 zone, about 6 in. in thickness, having a dip north 10° west 

 at an angle of 35°. The upper beds in the section have slid 

 over the lower ones, while the differential movement of the 

 mass has led to a discordant dip in the beds above as com- 

 pared with those below the shear plane, giving an appearance 

 <of stratigraphical unconformity (plate xix.). The zone of 



