110 



1865) ; and in 1877, in a letter to me, he writes : — " I am sur- 

 prised, pleased, to find that the Muddy Creek beds are above 

 the Murray Cliffs ; but what surprised me most is that you 

 regard the Mount Gambier beds as lower than either. This I 

 certainly did not expect, though I admit I had no good reasons 

 for my opinion." 



Neglecting the lower half of the chalk rock of the section at 

 Wilson's Bluff:, as from it I only gathered one fossil (Lima 

 armigera) , I find that the tout ensemble of the Bunda cliff and 

 Blanche Point cliff, Aldinga, to be the same. I cannot deny 

 that my opinion is not well supported by palseontological 

 observations, and that the lithological characters seem to be 

 widely different. Respecting the latter, it is after all more 

 apparent than real, and the Aldinga section, in some of its 

 details, closely resembles that which exists on a grander scale 

 in the Bunda cliffs. The band in which Salenia and W.insoluta 

 occur is at Aldinga a white limestone, with glauconitic grains ; 

 and the bed under the top limestone is at many places as highly 

 charged with polyzoal debris as the middle band in the Bunda 

 cliffs. I must declaim against my opinion touching the cor- 

 relation of the older Tertiary of the Bunda cliffs as being a 

 mere guess. It is certainly something more than what is 

 vaguely called an impression, for I have some basis for my 

 opinion, which is corroborated by that kind of intuitive per- 

 ception of the relation of things which comes from frequent 

 contact with the object of study in all the varying phases 

 which it presents. 



For these and the explicable reasons which I have stated I 

 see in the Bunda cliffs a stereotype of the Aldinga section, 

 with only a slightly different coloration. 



2Iinor Features. — The crystalline limestone is not a rock 

 absorbent to water, as may be inferred from the fact that all 

 the rock-water holes are in it ; but because of the many joints 

 and fissures which vertically penetrate its whole thickness, 

 the rain which falls on its surface is immediately lost to view, 

 and sinking through the yellow polyzoal bed, is somewhat 

 detained or directed to the front of the cliffs by the band of 

 hard chalk. 



Around Wilson's Bluff, where the yellow polyzoal bed is 

 thin, and the top of the chalk high up in the cliffs, it is only 

 the crystalline limestone that presents a perpendicular face, 

 whilst the long slope of chalk is encumbered with the blocks 

 of the upper bed set free by their weight pressing down on 

 the moistened surface of the chalk. This action has originated 

 the gulleys or steep-sided ravines which indent the escarpment 

 of the Hampton Range and the western 26 miles of the Bunda 

 cliffs. They do not penetrate beyond a few hundred yards 



