32 



•doubt, immediately overlie in that direction — appearing as the 

 surface rocks. The intervening country between the tertiary and 

 the mesozoic outcrops is occupied by basalt and drift accumula- 

 tions, so that no actual junction of the two formations can be 

 found. A little to the west of Merino, however, I have gathered 

 casts in ironstone of characteristic Muddy Creek shells in the 

 immediate vicinity of the underlying secondary rocks. Further 

 west still, on the Glenelg River, the mesozoic strata entirely dis- 

 appear, the marine tertiaries alone being visible, not only to the 

 border of the colony, but far beyond it. These deposits are, in 

 fact, found only as a fringe on the eastern, southern, and western 

 inargins of the mesozoic area, its central and northern portions 

 showing no signs of them, and it is doubtful, therefore, whether 

 the formation, as a whole, was ever covered by the tertiary sea. • 

 It has been thought by some geologists, whose opinions are 

 ■entitled to great respect, that the mesozoic beds pass under the 

 tertiaries right down to the coast, and also for long distances 

 both to the east and west. There appear to me to be some objec- 

 tions to this theory, which I will now state. 



1. There is no outcrop w^hatever of mesozoic strata in the 

 whole of south-western Victoria, except in the limited area of 

 the Wannon Valley. 



2. The shales, sandstones, and silicious limestones, of which 

 the secondary beds consist, are either horizontal or nearly so, 

 w^herever I have examined them, w^hile in order to pass, as sup- 

 posed, completely out of sight under the tertiary beds, they would 

 require to assume all at once a high inclination. Thus, near 

 Merino, the mesozoic strata are found at an elevation of 396 feet 

 above sea level, while on the cliffs of the Glenelg, only a few 

 miles to the Avest, a thickness of more than 100 feet of the 

 tertiary strata is exposed, the river having hollow^ed out its 

 channel to a great depth below the general level of the country. 

 Here there is no sign of the mesozoic strata, which we should 

 certainly expect to find if such horizontally disposed beds ex- 

 tended far in a westerly direction. Again, at Heywood (see 

 section, fig. 2), the tertiary strata have been bored into, to a 

 depth of 190 feet below sea level, in searching for water, with- 

 out discovering any change in the formation. 



3. The mesozoic strata are, I believe, of no great thickness in 

 this part of Victoria, and, therefore, not likely to prevail over a 

 wide area. The rocks underlying them, ^dz., micaceous, quartzose, 

 and felspathic schists (the so-called metamorphic rocks of the 

 •district), crop up at no great depth in two localities know^n to me, 

 one of which is about eight miles north of Coleraine, in the bed 

 of the Koroite Creek, towards the northern margin of the forma- 

 "tion, and the other, at about its centre, on the banks of the 

 Wannon, near the Winninburn homestead. 



