326 HISTOEY OF PETROLEUM OR ROCK OIL. 



from the absence of this substance diffused through the shales in 

 question, we are forced to assign it to a lower horizon, which is 

 doubtless that of the bituminous Devonian limestone. This view I 

 have for some time maintained in opposition to those who conceive 

 the bitumen to bo derived from the black pyroschists; see my lecture 

 before the Board of Arts, reported in the Montreal Gazette of March 

 1, where I asserted that the source of the petroleum was to be sought 

 in the bituminous Devonian and Silurian limestones; besides the cor- 

 niferous limestone (Devonian,) we have shown that both the Niagara 

 and the Trenton, (of Upper and Lower Silurian age,) contain petroleimi. 

 The question of the extent of the supply of petroleum is not easily 

 answered; the oil now being wrought is the accumulated drainings of 

 ages, concentrated along certain lines of elevation, and the experience 

 of other regions has shown that these sources are sooner or later ex- 

 hausted; but though the springs of Agrigentum, like those of Derby- 

 shire, have nearly ceased to flow, those of Burmah and Persia still 

 furnish, as they have for ages past, immense quantities of oil; nothing 

 but experience can tell us the richness of the subterranean reservoirs. 

 It is not probable that the Devonian limestone is equally rich in pe- 

 troleum throughout its whole distribution, but the exposures of it in 

 the west are too few to enable us as yet to say in what portions the 

 petroleum predominates; as, however, this rock underlies more than 

 one-half of the western peninsula, we may look for petroleum springs 

 much further east than Enniskillen. A well yielding considerable 

 quantities of petroleum is said to occur in the township of Dereham, 

 about a quarter of a mile southwest of Tilsonburg, and we may reason- 

 ably expect to find others along the line of the anticlinal, or of the 

 folds which are subordinate to it. 



It is now many years since Sir William Logan described the occur- 

 rence of petroleum springs in Gaspe, and collected specimens of the 

 oil, which are preserved in the Geological Museum. One of these, 

 near Gaspe bay, is described as occurring on the south side of the 

 St. John's river, about a mile and a half above Douglastovrn, where it 

 may be collected by digging pits in the mud on the beach. Another 

 locality is about 200 yards up a small fork of the Silver brook, which 

 falls into the southwest arm six or seven miles above Gaspe basin. 

 The oil collects in pools along the stream, and may be gathered in 

 considerable quantities. The cavities in a greenstone dyke on Gaspe 

 bay were also found to be filled with petroleum, and the odor of it 

 from the rock was perceived at a considerable distance. The dyke, 

 which marks a fold in the stratification, runs in the direction of the 

 petroleum springs, and the evidences of the distribution of petroleum 

 are thus, as Sir William Logan has remarked, visible along a line of 

 twenty miles. — (Report for 1844, p. 4L) Attention has recently 

 been drawn to these indications, and a company formed, with a view 

 of exploring this region for petroleum. Here, as well as in western 

 Canada and the United States, the connexion is evident between the 

 springs and undulations of the strata which favor the accumulation 

 of the petroleum. 



