286 FOSSILIFEROUS TUFF, ETC., AT CAVAN., 



seen in the Little River, cand the upper part at the Woinbargo 

 uplands. It rests upon the 'Lower Palfeozoic Foundation,' and 

 ill places has been let down by faults into it. Its lowest portions 

 approach the quartz porphyries in character, and in ascending 

 it becomes more and more fragmentary. It seems to me that the 

 facts I have detailed naturally lead up to the inference that in 

 tlie Snowy River Porphyries we may see the accumulations of 

 ash, agglomerates, and lavas due to former volcanic activity in 

 Palaeozoic time. Those rocks whose characters are obscure may 

 well be regarded as having undergone such changes that former 

 beds of fine ash, or even of agglomerates, may have become 

 structureless rock masses of silicious and felsitic character." 



These remarks of Mr. Howitt's will also apply equally to the 

 rocks of the Cavan beds. 



In another place in the same paper he goes on to say, in refer- 

 ence to some displaced rock masses: — "Here and there these great 

 rocks beautifully showed their fragmentary nature, as well as 

 the composition of the jutting cliffs far above our heads from 

 which they had fallen. They were, as usual, composed of angular 

 fragments of quartziferous, or fine-grained, or coarse porphyritic 

 felstones, or of the compact or banded varieties. Many of the 

 included blocks were up to two feet in diameter; and in one 

 enormous mass I observed, together with a beautiful assortment 

 of varieties of felstones and quartz porphyries, a fragment of 

 'well marked granite. It is worthy of note that I nowhere 

 observed in these agglomerates any fragments of sedimentary 

 rocks." 



This statement agrees with what I noticed at Cavan, for I 

 found many displaced blocks of a brecciated nature containing 

 angular fragments of porphyries and banded felsites. The more 

 I read of this interesting description of the Victorian rocks, the 

 more I was inclined to link the Yass series with them; a differ- 

 ence arises when the author states : — " And I noted also one 

 circumstance worthy of consideration, that scarcely an instance 

 was to be observed of such appearances as might be referred to the 

 action of water in sorting and arranging the various beds. 



