GLACIAL DEPOSITS OF BACCHUS MARSH. 383 



will be seen that if this 100ft. bed had been laid down before the 

 basaltic overflow b)' any cause, glacial or otherwise, it could not 

 include angular fragments of the basaltic sheet that flowed over 

 it subsequent to its deposition, and this it does. 



Nor have we as yet observed the basaltic overflow reposing 

 directly upon this unstratified material, although Fig. I. of the 

 section given by these gentlemen makes it appear so, but wherever 

 seen it reposes directly either on the granite, Silurian, the old drift 

 deposits — Triassic sandstones — or on the so-called Miocene leaf- 

 beds, but not on this re-dei^osited material. 



And further, these basaltic fragments are found — in places — to 

 increase in number as the basaltic sheet is approached, due, 

 evidently, to the breaking away of the edges of the sheet, which of 

 course gravitates to lower levels along the valley sides among the 

 surface material. 



The general characters of the conglomerates, as understood by 

 Messrs. Officer and Balfour, " much incline them to the opinion 

 that they would turn out. to be, not an ' iceberg drift ' " — as the 

 eminent geologists before mentioned proclaimed the conglomerates 

 occurring in the S. and E. of the area mapped by us to be, and 

 which we find underlie and are intercalated with the Triassic sand- 

 stones — " but in reality till or boulder-clay, in fact the ground 

 moraine of glaciers." 



These characters they sum up to be — First, " the unstratified 

 nature of the clay matrix," but we have seen that the rocks 

 throughout this area, though sometimes disturbed and contorted 

 are unmistakably stratified, so that it is rare that any difficulty is 

 met with in obtaining the strike and amount of dip, and that the 

 only unstratified material to be found is made up of hill wash or 

 talus, river wash, small slips, and denuded material reposing on 

 the flanks and edges of the stratified rocks and some of the con- 

 glomerates. 



Their second reason for believing this " imstratified " material 

 to be due to a ground moraine is " the number and variety of the 

 included stones." The stones, however, as has been pointed out, 

 are precisely similar in character to those in the recognised older 

 rocks (Triassic sandstones) ; and the larger proportionate number 

 of stones occurring on the unstratified surfaces is due to the well- 

 known circumstance that ordinary denuding forces naturally 

 remove the fimer materials first, leaving the coarser material behind. 



This is even more strikingly shown in the case of material 

 brought down by torrentous rivers, as some of this appears to have 

 been, and this probably accounts for the greater proportionate 

 number of stones occasionally observed both by them and our- 

 selves. 



Their third reason is "the striated and glaciated aspect of 

 many of these stones," but, as they have themselves well observed, 

 " some stones in this material do not retain their striated and 



