192 Proceedings of the Royal Society of Victoria. 



ice ; any scouring action by the sub-glacial river would tend in the 

 direction of wearing away the ice nearest to the bottom of the 

 sea, and there would thus be a space more or less great 

 according to circumstances between the lower side of the advanced 

 ice and the bottom of the sea, and the sub-glacial streams would 

 in consequence be unhindered in the distribution of their 

 suspended matter. The disturbance and commotion which takes 

 place when a berg is broken off and while it is seeking its position 

 of equilibrium confirms the view just stated that between the ice- 

 front and the sea bottom their exists a layer of water. In our 

 view we must I'egard the sub-glacial streams as flowing for a 

 longer or shorter period beneath the protruding ice-front ; the 

 matter held by them in suspension is being deposited in stratified 

 beds beneath this tongue, which, as it slowly melts by its contact 

 with the water, must drop the striated boulders, etc., it contains 

 into the subjacent beds. If the ice-tongue continue to exist for 

 a long time before the berg is broken off we should have a 

 considerable profusion of included material in the beds beneath. 

 With the separation of the berg mass from the parent tongue 

 another set of conditions would arise ; the formation of stratified 

 beds by the sub-glacial streams would continue as before, but as 

 the source of supply of striated stones, boulders, etc., has been 

 removed by the floating aw^ay of the berg, the stratified beds 

 should be almost entirely free from included matter, the only 

 source of such material now being chance icebei-gs which might 

 float over the site formerly occupied by the ice-tongue. In course 

 of time the advance of a second tongue would lead to a repetition 

 of the conditions favourable to the formation of stratified beds 

 ■containing boulders, etc. In the sections along the Goodman's 

 Creek we have both sets of beds displayed, the one rich in 

 included material, the other destitute of it, but overlain by a 

 second bed containing large quantities of boulders, etc. That 

 a certain amount of the fine-grained material composing the 

 stratified beds has melted out from the ice-tongue is probable ; 

 and though this would not interfere with the stratification of the 

 beds, we are inclined to regard the sub-glacial streams as the 

 principal agents in the formation of the stratified beds. It may 

 also be pointed out that stratified beds with few included bouldfers 

 might result during a climatic recession of the ice-front. 



