:384 E. ^Y. Sknds: 



•one stated, that the deposit is essentially a Kainozuie iiioiiehiquite 

 .agglomerate, formed from an explosive type of volcano, which. 

 -bursting through a deposit of Permo-('arl)oniferous glacial con- 

 glomerate, incorporated a certain p)-oportion of glaciated pehbles 

 and finer deti'itus among the volcanic ejectamenta. and that 

 subsequent denudation of the area has removed all the glacial 

 material except where the neck of the volcano is now exposed to view 

 in Kangai'oo Gully. 



Summary. 



A volcanic agglonierate, contaiiiiii<i- glaciated pebbles, and in- 

 vaded l)y a monchiquite dyke occui-s at Kangaroo Gully, near 

 Bendigo. It junctions nearly vertically with Ordovician slates and 

 sandstones, and appeal's to be the outci-op of a volcanic pipe, ellij)- 

 tical in outline, and stretching X.X.W. and S.S.E., aljout | mile 

 long, and 40-70 yards bioad. The pipe has been peneti'ated by 

 shafts and bores to 104 feet. The bulk of the material consists of 

 monchiquite agglomerate similar petrologically to the dyke which 

 penetrates it. Chemical analyses show some similarities to the 

 dyke, but it is abnormally low in alkaline earths (3 per cent.), and 

 abnormally high (13.5 per cent.) in alkalies. These results appear 

 to be due to obscure subsequent alteration of the rock. 



The agglomerate, especially near the outcrop, contains abundant 

 pebbles, some of which are definitely glaciated, and contains 

 scattered grains of quartz, apparently throughout. After consider- 

 ing various alternative explanations of tlie mode of occurrence, it 

 is suggested as not improbal)le that in mid-Kainozoic times explosive 

 volcanic activity formed a vent, which penetrated a deposit of 

 Permo-Carboniferous glacial matt-rial, and incorj^orated some 

 glacial pebbles with its fragmental ejectamenta. Subsequent 

 denudation removed all traces of glacial material, except Avheie it 

 was embedded in the neck of the volcano. 



EXPLANATION OF PLATE XXXII. 



Fig. 1. — Facetted and striated glacial ([uartzite pebl)le fiom out- 

 crop of deposit in Kangaroo (iully. About s natural size. 



Fig. 2. — Photomicrogiapli, Section Xo. 100!). x 25 diameters. 

 •Vgglomerate type of deposit, in which glaciated pebbles 

 (iccnr. 'I'jic section shows anguhir and corroded (piartz, 

 and fragments of monchiciuitc and (juartzite in a volcanic 

 nnitrix. Forty yards south of noi-th end of deposit. 



