246 Proceedings of the Royal Society oj Victoria. 



Wellington Parade, 15 feet of clays lie on Silurian claystones. 

 The basalt has not been pierced in any of the shafts hereabouts. 

 In parts of Yarra Park the basalt is covered by only a few 

 inches of sandy alluvium, and along the fringe of the river, basalt 

 may be seen in several places running to the edge of the stream, 

 though not visible in the bank. 



From being only a few chains wide at each end of the area 

 under review the basalt reached a width of about 30 chains in 

 the middle. Whether the whole of this flow came down through 

 the narrow neck east of the Cremorne Railway Bridge, or some 

 of it over the low Silurian rise between East Richmond and the 

 railway is not apparent. 



The Silurian rocks form interesting sections near both entrances 

 to the Botanical Gardens from the Yarra side, and also from the 

 Old Pumping Station to near the Engineers' Depot. Here a 

 line section discloses what appears to be a local example of qua- 

 quaversal dip, and two interesting dykes. These are quite 

 distinct in character from each other. The more eastern one, 

 which is about 3ft. Gin. wide, and bearing north and south 

 obliquely across the beds, dips about W. at 60°. It is so 

 decomposed that its original character is not detectable. It has 

 the appearance, however, of having been of a mica felspathic 

 nature, and black mica (biotite) is still visible though mostly 

 decayed, giving the rock a rusty brown color. The beds on the 

 foot wall are considerably crushed and twisted for a few feet 

 back from the dyke. The other and much larger dyke has been 

 intruded along the bedding plane of the strata, and stands out 

 prominently in color from the containing beds. From a short 

 distance it appears to be one of the beds themselves, but closely 

 examined it is seen to have entangled in it two small blocks of the 

 sediments which show in such a pronounced manner that there 

 is no mistaking the fact. The dyke rock is a tine-grained white 

 granular one of apparently quartz and some glassy felspar, the 

 latter predominating. 



The strata here dip generally S. 70° W. at angles varying from 

 53° to 58° to the west of the dome, and N. 35° E. at from 30° to 

 35° to the east of it. In the section near the western Yarra 

 entrance to the Botanical Gardens the rocks dip from W. to S. 

 80° W. at from 29° to 39°, while at the eastern entrance the dips 



