Geology of the Lower Moorahool. 45 



zone (6, p. 76). Graptolites of a slightly iiigher horizon occur 

 in Sutherland's Creek, and a few that may be of the same 

 age at the localities shown on Quarter-sheet II), S.W., in the 

 Moorabool Valley. The reason, then, for the absence of gold in 

 the gravels appears to be that they have been derived horn a 

 barren belt of Ordovician, and not that the charactei- of the 

 quartz veins depends on the age of their formation. 



At the locality marked W.T.M.8. on the Quarter-slieet the 

 summit of the Ordovician is about eighty feet above the level 

 of the river, which flows through a rugged gorge. Half a mile 

 below this the gravels pass up into marine beds. 



These consist in the main of polyzoal limestones, and are 

 strongly current bedded, containing quartz grains the size of a 

 pea, as well as numerous flakes of slate. In places the limestone 

 is crowded with vast quantities of the peculiar little echinoderm, 

 Fibularia. These beds, which are a part of the " Lower Maude 

 Series," are probably about the level of Lethbridge Station, 

 which is 547 feet above sea level, and ai-e the most northerly 

 exposure of the marine beds. From here the surface of the 

 Ordovician drops rapidly as we go South, and in about two miles 

 it has disappeared beneath the level of the bottom of the valley. 

 The Lower Maude series of marine beds, which have now almost 

 entirely displaced the gravels, disappear in the same way a little 

 further down stream, as showui on the Quarter-sheet. The section 

 just above this is described in a previous paper (2) ; but it may 

 be recalled to mind that the surface of the Older Volcanic rock is 

 about 190 feet above the level of the stream, which has a fairly 

 rapid fall. The limestone and sands overlying the Older Volcanic 

 rock may be traced continuously for four miles to the southward, 

 when we reach the quarry opposite the Clyde School (2, p. 183). 

 Here the surface of the volcanic rock has dropped to about 40 

 feet above the level of the stream, in spite of the rapid fall of 

 the latter. The Upper Maude limestone is now overlain by 

 fossiliferous clays,, into which it passes upwards, the fossils from 

 the clays showing, as we have previously pointed out, the closest 

 agreement with those of the clays associated with the Batesford 

 limestone. About a mile and a half further down the stream we 

 recently noted the most southerly outcrop of the Eocene basalt, 

 namely in Section IV., Allotment B, Parish of Darriwill. The 



