On the Marine Rocks underlying Warrnamhool. 95 



penetrated similar sediments for 2100 feet, without toucliing 

 the Paleozoic bedrock. 



A reference to the accompanying table of strata traversed 

 by the Warrnambool bore, and prepared for this paper by 

 Mr. Richard Bennett, will shew that the uppermost stratum 

 consists of SI feet 9 inches of limestone traversed by flint 

 bands. This rock is of clastic origin, being composed of 

 comminuted shell mixed with silicious sand, and bound 

 together by a calcareous paste, and containing an abundance 

 of flints. It is an ordinary littoral deposit. Mr. Bennett 

 regards it as identical with the jBolian limestone so 

 abundant on the coast in the same neighbourhood, which 

 it does resemble, both of them being accumulations of broken 

 shell. I think, nevertheless, that the flint bands of the bore 

 limestone differentiates the two deposits sufficiently. We 

 know that when silicious sand is associated with calcareous 

 sand, and the rock is below the line of saturation, the silica 

 is rendered more or less soluble, and colloid silica segregates 

 out of the mass just as do septaria in clays, and it thus forms 

 flint nodules. This operation cannot proceed in a dry rock, 

 as far as I know, and therefore flint bands in a limestone are 

 evidence of that limestone having been innnersed in water. 



The cieolian coast limestones of Warrnambool do not 

 contain flints, except as remanies, as far as I can ascertain 

 from some slight personal examination, and also from enquiry ; 

 and as they are quite recent as to age, and have never been 

 submerged, it is unlikely that they would. The bore lime- 

 stone on tlie other hand, was accumulated under the sea, 

 and the flint bands attest this cii'cumstance. 



The three next beds in descending order are all clays, 

 either red or yellow. They were deposited when this 

 locality was more distant from the coast line, than it was 

 when the just described and more recent calcareous sand- 

 rock above it was accumulated. The order of superposition 

 is evidence in favor of an elevatory movement, gradually 

 bringing the area into shallower water, so that the deep 

 water clays become buried under shallow water sands. 



Bed No. 6. Calcite, 9 ft. 5 in. Thick. 



This is an uncommon formation. Nearly all limestone 

 is composed of the comminuted remains of shells and corals 

 bound together by calcareous paste ; but this massive 

 stratum contains no clastic materials whatever, judging from 



