54 



Personal Observations in the 



who are proverbially the best riders in the country, and sur- 

 pass anything we read of concerning the horsemanship of 

 other countries ; this superiority being attributable only to 

 the rugged nature of the district in which they reside. 



II. Melbourne, as is well known, rests on strongly com- 

 pressed Silurian strata, entirely surrounded by the basalt 

 formation. Extremely minute fossils {Atrypa) are found in 

 these strata ; but those typolites obtained near Flemington, 

 scarcely two miles from Melbourne, and of which I have pro- 

 cured living specimens from Western Port Bay, are large and 

 perfect. The latter are petrified in brown iron ore belong- 

 ing to the uppermost tertiary formation. 



The extensive ]jh\ins between Melbourne and Mount 

 Macedon, as has been stated in the former part of this 

 paper, belong almost entirely to the basalt, or, as some Eng- 

 lish geologists term it, the trap formation. The rocks of 

 this class are composed principally of felspar and augite, the 

 latter predominating ; and a soil of very superior capabilities 

 arises from their decomposition. 



The trap rocks which occur throughout Victoria, I have 

 arranged under two distinct heads, viz., basalt proper, and 

 dolerite; the former a black homogeneous mass, sometimes 

 impregnated with different zeohtes and iron ore. That 

 both are the result of volcanic action there cannot be ^ the 

 slightest doubt, as they exhibit the most unmistakable signs 

 of having been once in a molten state. 



The different varieties of basalt which occur in the plains 

 above mentioned are : — - 



1. Common basalt or bluestone; in columnar platforms 



and irregular boulders. 



2. Porous basalt in irregular forms ; on account of its 



porosity unfit for building purposes. 



3. Pumice stone, like basalt. Swims in water ; attracts 



and retains the heat very powerfully. 



4. A lithodomous mass of an ochre-brown colour ; easily 



crumbled. It is questionable whether it be not of 

 aqueous origin, its formation taking place when the 

 volcanic power was finally subdued. 



5. Black soil of a crumbhng nature. The decomposition 



of this species produces a soil highly valued for agri- 

 cultural purposes. When mixed with clay the ground 

 becoming what is termed by the colonists ^^honey- 

 combed;" and if stones be intermingled with it, mounds 

 are raised, designated " dead men's graves." 



