388 PROCEEDINGS OF SECTION C. 



for a few yards, and as in the case under consideration, near an 

 early worked quariy on otherwise locally disturbed surface, we 

 have no need to call in their aid. The above explanations, or jDer- 

 haps the early operations of the quarrymen, or both, will be ample 

 to account for their presence as found, and, as for the " boulder 

 -till," it has been shown that the material mistaken for it is of 

 comparatively small amount, and of superficial character, and this 

 small amount is often on ledges and slopes, where, if it had not 

 recently been placed, it would ine^-itably and quickly have been 

 dislodged in preference to the lower rock in the supposed ancient 

 valley. So that, instead of there being tM'o classes of unstratified 

 rock here, formed by two systems of glaciers somewhere in the 

 Mesozoic and Tertiary ages, and separated by the Triassic sand- 

 stones, we have simply the stratified rock, mudstoue, and sand- 

 stone (Triassic sandstones), and conglomerates, including in their 

 mass the various classes of rock mentioned above, but much more 

 extensively developed than has hitherto been supposed, for on the 

 estimated average of the dip, examined at about 100 places across 

 the whole area, it would appear that we should be justified in esti- 

 mating the thickness of this formation at approximately 5,000ft. 

 But, it is stated, " it was probably overflowed by Pliocene basalt, 

 which would be the means of protecting it for a considerable 

 period." Now, it is found here, as at many other places, that 

 where ancient valleys have been filled with basaltic flows these 

 become the most dense and tough, and generally form an almost 

 impregnable barrier to erosion, and places so covered are of all 

 others most likely to keep sealed up any deposits over which they, 

 are laid. And, further, though the erosion has certainly been great, 

 if it had been sufficient to have removed every vestige of basalt 

 from valleys where it had been hundreds of feet thick, it would 

 undoubtedly have removed this small amount of easily denuded 

 material. 



The evidences appear to us to support — 

 1. The reference of the early-noticed conglomerates by the 

 first and able geologists of the Geological Survey of 

 Victoria, and of the present departmental officers, and 

 Mr. Oldham, of the Indian Geological Survey, to their 

 deposition under water by the agency of floating ice near 

 shore, and to their final arrangement by the moving 

 waters. 

 II. Also, the theory that the sandstones and mudstones, and 

 other conglomerates intercalated between these, but lying 

 to the north, east, and west of them, including those known 

 as l^acchus Marsh Triassic sandstones, have been laid 

 down under water, and probably belong to the same gi-eat 

 deposit, and have resulted from similar causes ; the beds 

 now dip in a general southerly direction towards the 

 present sea. 



