16 Victoria as a Field for Geologists. 



to the harmonies equally conducive to picturesque effect. 

 To show that discoveries of both these kinds are likely to 

 reward the Geologist in Victoria is the task undertaken in 

 the present paper. 



Commencing with what is commonly looked upon as the 

 verj" lowest rock, we find that granite is by no means 

 sparingly developed in this portion of the world. Generally, 

 however, it is not a favourite subject for study. In most 

 text books the same is regarded as a sort of foundation upon 

 which the entire superstructure of geological formations is 

 erected ; the floor on which the newer rocks have been spread 

 out, if not the grand storehouse from which the debris — now 

 hardened into stony masses — has been obtained. It is 

 often, furthermore, spoken of as the solidified crust of a once 

 entirely molten globe. Because this last opinion is just now 

 rather warmly controverted, the careful study of granite 

 bids fair to become one of more than ordinary interest. It 

 is, you will remember, commonly formed of three separate 

 constituents, quartz, mica, and felspar, and these are not 

 found to assume any definite order, but are promiscuously 

 scattered, in distinct crystals, throughout the entire mass. 

 This an^angement was long supposed to be a result of the 

 separate ingredients crystalizing while the whole, under 

 enormous pressiu^e, cooled slowly from a state of fusion. It 

 is argued, however, by no less a chemist than Dr. Percy, 

 that the contained quartz, at least, is evidently rather of 

 aqueous than of igneous origin. In support of this theory, 

 quartz, or more properly silica, is said to assume two separate 

 forms, the crystaline and the amorphous. The former, in 

 which is included flint and chalcedony, together with 

 regularly crystalized quartz, has a high specific gravity, 2-6, 

 is almost insoluble, even in hot alkaline solutions, and has 

 often been most unmistakably formed from a liquid menstrum. 

 The latter variety, on the other hand, is of low specific 

 gravity, 22 or 2"3, is soluble to a great extent, and is the 

 very form assumed when small particles of silica have been 

 melted by an intense heat. Now the quartz of granite is 

 ever of the former, and never of the latter kind, and, whilst 

 distinct crystals of quartz have been repeatedly produced in 

 what is called the wet way, all attempts to obtain them by 

 fusion have signally failed. 



The foregoing is one of the objections recently raised 

 against the old fashioned theory. Further occasion will be 

 given for alluding to the subject under the head of quartz 



