332 ■ Albert V. James: 



Palaeozoic C'o/if/Ioitir/afes-.—'r\[e four palaeozoic conglomerates 

 in this area have been carefully described by T. S. Hart (5). C^, 

 the most nortlierly, is wrongly coloured tertiary in one of the three 

 quarter sheets. It has Ijeen pointed out (6) that this conglomerate 

 has been so indurated by thermal nLetamphorism that the matrix 

 is as hard as the old quartzite pebbles, and thus the pebbles do not 

 weather out. 



Ihe southern exposure C.^ can be picked up in a runnel on the- 

 cliff about 80 ft. above the stream. It is not altered to the extent 

 that d is. 



Cj shows the clay bands much distorted by differential pressure, 

 as they are in the Italian Cutting, Daylesford (8). 



Q is the largest of the four conglomerates. 



T. S. Hart (6) puts forward various reasons for considering it 

 an Ordovician glacial conglomerate. His conclusions appear in- 

 correct. The following is a summary of the reasons given on which 

 he based his conclusion : — 



(1) A part of the conglomerate is a mixture of pebbles and 



fine clay. 



(2) The strata are much disturl;ed in places. 



(3) The matrix is angular. 



(4) Some pebbles are facetted and striated. 



(5) Fossils are absent on account of severity of the climate- 



at that period. 



The writer carefully weighed these points, l)ut was forced tO' 

 discard the theory of the glacial origin. A mixture of pebbles and 

 clay can be formed in other ways than by glacial action, and the- 

 disturbance of the strata appears to be the unconformable junction 

 of the Ordovician and Silurian. The presence of the striations on 

 an insignificant percentage of the pebbles can be accounted for" 

 by the fact that when conglomerate bands are folded under pres- 

 sure, the hard pebbles grind against and scratch one another. 

 Facetted pebl)les were not common in this congl'omerate, and 

 there was quite as large a percentage in the river conglomerate- 

 as in the ancient collection. On examining under the miscroscope, 

 the matrix from conglomerate C. and comparing it with material 

 taken from other strata, it did not appear to be more angular 

 than the latter. It has been shoAvn' already that life was abundant- 

 in the seas in that age. 



The direct evidence against this glacial theory is : — 

 (a) Ihe general linear arrangement of the pebbles. 



