376 Revieio of Recent Oeological Literature. 
in the latter part of his discourse. No gas or oil well has ever 
been known to aflford a pressure greater than that due to its 
depth, or indeed equal to it. No oil well has flowed except in 
diminishing quantity even for a few years, nor has the oil per- 
manently reached the surface. Nor does the ability of reach- 
ing greater depths afford us any hope. Already the wells are 
far below all the productive strata. Three thousand and even 
four thousand feet have been penetrated and the ancient 
gneissic rocks have been reached in the United States, while 
in Germany even this has been surpassed and the augur has 
been down five thousand feet below the surface and the latest 
report gives the actual deepest boring at 5,735 feet, or consid- 
erably more than a mile. But the lowest oil-bearing strata in 
North America are only about 1,500 feet down, and it is rare 
indeed to find any valuable yield beloAv that depth. In the 
Caucasus the beds are, we understand, even nearer to the sur- 
face. All analogy and all probability, are therefore, against 
the chance of our ever finding gaseous or liquid fuel at great 
depths in the crust and the idea of going down below the 
Palaeozoic strata in search of oil or gas in the hope of winning 
them from the old Archaean rocks below can find no place in 
the mind of any one of sound judgment and practical experi- 
ence in the subject, be he chemist, geologist or only well- 
sinker. 
REVIEW OF RECENT GEOLOGICAL LITERATURE. 
Address to the Geological Section of the British Associatio7i. By James 
Geikie, LL.D., F.R.S., president of the Section. Newcastle-upon- 
Tyne, Sept. 12, 1889. pp. 27. (A reprint of this address, excepting its 
two introductory pages, is given in the Geological Magazine for Octo- 
ber). The subject is the recent progress in glacial geology, with ref- 
erence chiefly to the limits, and to the marginal moraines and other 
drift deposits, of the ice-sheet of northwestern Europe, together with 
its relation to the loess, to interglacial epochs, and to the antiquity of 
man. 
Professor Geikie recounts the phases of opinion that have pre- 
vailed among German geologists concerning the origin of the drift. 
At first submergence and icebergs were appealed to as explaining 
everything ; but since Dr. Otto Torell, in 1875, first stated his belief 
that the "diluvium" of northern Germany was of glacial origin, ingen- 
ious attempts have been made to show that the drift was formed 
partly by floating-ice and partly by land-ice, until witli extended 
