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SEARCH FOR PETROLEUM. 



I am confirmed in the opinion that we have been led to the 

 belief that subterranean stores of petroleum exist in this colony 

 from the fact that spurious substances, met with at the surface at 

 several and distant parts of this colony, have been regarded as 

 having an origin in common with petroleum. In all cases of 

 reported discoveries the petrological associations have been 

 adverse to the petroloid nature of the materials, whilst chemical 

 investigations have dispelled any hope of their value as sources 

 of petroleum which may have been fostered by their external 

 appearances. Among these spurious substances, we may 

 mention the so-called Coorongite, which has neither the 

 chemical nor the physical properties of Elaterite — -it is not an 

 inspissated mineral oil, but is the remains of a vegetation 

 which grew where the Coorongite now exists. If, therefore, 

 success should attend the boring operations of the Salt Creek 

 Petroleum Company, the existence of petroleum at a consider- 

 able depth and the dissimilar Coorongite at the surface will be 

 merely a remarkable coincidence. Another spurious substance 

 is the peaty infilling of a copper lode at Moonta to a depth 

 of 120 feet. Other substances are soils impregnated with 

 resin of the grass-tree, or with the liquefied dung of wombats, 

 sheep, &c. 



The origin of petroleum is not yet a solved problem, but that 

 it is connected with plant remains, marine or terrestrial, or 

 with animal debris, scarcely admits of dispute. Some oil shales 

 are undoubtedly carbonaceous muds, the carbonaceous matter 

 being derived from organic debris entombed with the original 

 sediment. But the exact process of the natural manufacture 

 of oil, or of its transfer from its original site to those beds in 

 which it is now stored, is utterly unknown. The chemical 

 theory which regards petroleum as condensed gas — the gas 

 having been previously distilled from oil shales — does not 

 satisfy all the phenomena of its occurrence. 



Nevertheless, keeping in mind the organic origin of the 

 carbonaceous material of oil shales, it is obviously incompatible 

 that a volatile oil should be present in rocks which have been 

 subjected to high temperatures. We should, therefore, not 

 expect such rocks as mica slate, gneiss, granite, &c., which are 

 highly altered rocks, to yield oil ; though it is possible, but 

 most' improbable, that such may have acquired some slight 

 bituminous infiltrations derived from the distillation of the 

 oily matters from adjacent bituminous beds. The higli antiquity 

 and the highly metamorphic character of the Pre-Silurian rocks 

 preclude all reasonable hope of finding stores of bituminous 

 matter in them. Eocks of this age occupy the Cape Jervis Pro- 

 montory, and extend eastward, at the surface, to Middleton, and 



