martix.I PETROLEUM IN CONTROLLER BAY REGION. 25 
some of the wells would have been more successful if they could have 
been continued to greater depths. 
Three wells which were located on mud flats at some distance from 
high land or from exposure of solid rock had difficulty or did not 
succeed in reaching bed rock. In two cases the drivepipe Avas sunk 
to depths of 240 and 580 feet through mud without reaching solid 
rock. These instances show conclusively the inadvisability, in the 
present stage of development, of attempting to locate wells on the 
flats. After a field is proven, then the mud flats adjoining it longi- 
tudinally may be considered to have a speculative value. At present 
there is no indication that they are worth anything. 
Another instance illustrating the folly of investing in the low 
grounds, and also of investing without thorough investigation, is the 
case of a tract which was staked and sold for $1,700 during the past 
winter. In the spring the supposed land floated and melted entirely 
away, the stakes having been driven in the ice off the shore of Con- 
troller Bay. It is generally believed in the region that there was no 
intent to defraud. 
Structural relations of the petroleum. — The conditions believed by 
the majority of observers to be necessary to the occurrence of petro- 
leum in commercial quantities are, first, the presence, originally, of a 
large amount of organic matter in the sediments from which the oil 
was derived ; second, the existence of a porous rock, in the aggregate 
very considerable, in which the oil could accumulate, and, third, the 
protection of this rock in such a manner that the oil can not escape. 
The condition generally regarded as affording the most efficient pro- 
tection is the presence of an overlying stratum of fine compact rock 
which the oil can not penetrate and the flexure of the strata into a 
gentle anticline, so that escape of the oil is cut off both in an upward 
direction and laterally — in the latter case, it may be, by the body of 
water behind it. Other conditions which govern the accumulation 
and distribution of oil are changes in the porosity of the containing 
bed, either from variation in the coarseness of sediment or from the 
filling of the interstices with mineral deposits, such as carbonate of 
lime. Underground water also doubtless plays a part in the accumu- 
lation and distribution of oil. 
From the size and distribution of the seepages it may be reason- 
ably inferred that a vast amount of organic matter which was sub- 
sequently converted into petroleum Avas incorporated with the sedi- 
ments now constituting the oil-bearing shales of the Controller Bay 
region ; the appearance of the rocks is evidence that there are numer- 
ous horizons in the series sufficiently porous to afford reservoirs for 
the accumulation of oil, and the successful wells show that the condi- 
tions are favorable for at least one productive field. Conditions 
below the surface are, however, frequently very difficult even to 
