396 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 7, 



field "in law," belong to the same auriferous tract, geologically- 

 speaking. 



[On a MS. sketch-map accompanying this memoir, the author 

 has laid down the principal water-courses and ranges for several 

 miles round Creswick Creek, and also Eureka, but not the interme- 

 diate country, on account of the distance.] 



In the following description I shall confine myself to the auriferous 

 region of the '' Ranges," for the basalt which hems it in on the east 

 and west may be regarded only as a frame to the picture. 



The general character presented by the gold-fields is an undulating 

 surface, with steeper slopes where the slaty rock protrudes, and gentler 

 slopes in the low lands, where the soil is composed chiefly of quartz 

 debris, and is covered by the monotonous vegetation of the gum-tree. 

 The features of the gullies and hills are so much alike, that when the 

 traveller has seen one portion he knows the appearance of all. This 

 tract is watered by creeks, which in summer generally dry up en- 

 tirely unless they spring from the basalt : near Creswick Creek all 

 the springs flow from that rock ; and you can tell their position from 

 a distance if you see a tea-tree. The basalt forms plateaux, not 

 thickly timbered, but producing excellent grass ; hence most of the 

 squatters have picked out this ground for their "run." The general 

 aspect of the vegetation enables you to draw the boundary of the 

 basalt; for on this rock the "white gum-trees" are predominant, 

 whilst on the auriferous ground the "stringy bark gum-trees" are 

 almost exclusively seen. 



The general geological character of this tract is "quartz-schistose," 

 which is covered in the plains by drift or alluvial soil. " Quartz- 

 schistose" is the misapplied term employed here to signify an in- 

 definite succession of strata of clay-slate and of argillaceo-arenaceo- 

 micaceous slates, interstratified apparently, as regards their strike, 

 with quartz-veins of all sizes. These veins, however, appear to tra- 

 verse the slates on their dip (figs. 1 and 2), as at Black Hill near 

 Ballarat, where the quartz-veins are regular lodes. 



Figs. 1 & 2. — Quartz-vein in slates at Black Hill, near Ballarat. 

 Fig. 1. Fig. 2. 



==;=J^-f^^^-===E^ a. 



-■ - - ---_ - r-_ -_.--_--- 7. 



Zir"_~":^ — '~r 



rr:r ~r :—^ — ' " 





c 



z ■ 



: d 



a, b, d. Slate-rock. c. Quartz-vein. 



The strike or bearing is, as far as I have observed, generally north 

 and south, dipping very commonly 85° and more to the east, but 



