26 Notes on the Diabase Rocks 



4. Purple to reddish indurated mud. The lower part of 

 this bed is full of large rounded boulders of No. 3. It is 

 three feet in thickness. 



5. A fragniental bed, three feet thick. The fragments are 

 subangular, arid under 5 inches in diameter. They all seem 

 to be varieties of felsite. 



6. Purple indurated mud, two feet thick. 



7. Coarse breccia conglomerate. The fragments under 

 six inches diameter and of varieties of felsites, white to 

 purple in colour, or banded in different shades of colour. This 

 bed is four feet thick, and weathers very rapidly. 



8. Yellowish brown clayey material, two feet in thickness. 



9. A fragniental bed, six feet in thickness. The frag- 

 ments under three inches diameter. A slice taken from a 

 portion of the finer-grained materials showed them to con- 

 sist of angular and subangular pieces of felsite, of crystaline 

 quartz grains, and of more or less broken crystals of ortho- 

 clase and of plagioclase, the former being most numerous. 

 The fragments are cemented together by lesser fragments of 

 the above, filled in throughout the inter-spaces by quartz 

 and chalcedony. 



10. An earthy bed enclosing felsite fragments. There are, 

 however, two bands in it of more indurated material. This bed 

 appears to have been a felsite ash or tufa, three feet thick. 



11. Indurated materials, resembling No. 10, and two feet 

 thick. 



12. A yellow earthy bed, containing numerous fragments 

 of felsite under one inch diameter. 



13. A bed a foot thick of minute fragments, resembling 

 an ash or tufa. 



14. Grey compact limestones, dipping W, at 15°. 



The total thickness of beds is about 46 feet; and Nos. 4 to 

 13 conform in general dip to No. 14. 



This section shows clearly that the limestones have been 

 laid down upon the Diabase porphyrites and on the passage 

 beds connected with their abraded surface. It is also 

 evident that at the time the sediments were formed part of 

 the felsitic materials resembled a volcanic ash. The vesi- 

 cular nature of the upper surface of the Diabase porphyrite 

 also points to its having probably been a lava ; and looked at 

 by the light of evidence furnished by the natural sections 

 to be seen in the district, it was most likely poured out on 

 the coast line of a sinking volcanic land. 



In tracing down the river from this point to its junction 



