Clay-balls, etc., from Banter Sandstone , Notts. 
83 
In every case these striai occur' on the polished surface and 
never on that part which has not been embedded in the clay. 
Indeed, it often occurs that the little pittings on the stone have 
been filled in with compressed cla\-, and the moving clay 
has ridden over these particles of compressed clay and dug 
fnto the stone on the opposite side, thus producing micro- 
scopically grooved hollows which bring to mind some of the 
most interesting effects of glaciation. 
Another suggestion has been made, viz., that the polished 
pebbles are in their natural condition as they occurred on the 
Desert Sand in Bunter times, and that being embedded in 
the clay has preserved them from being subsequently roughened 
by continual movement in the sand. 
But the little grooved hollows just mentioned are contrary 
to this idea, because they show cutting as well as polishing, 
and again under the miseroscope it is seen that the surface has 
been dug into by the moving clav, i.e., polishing has reduced 
the surface of the stone, and this is quite contrary to what 
we should expect if the polish were the original condition. 
— : o : — 
The Nature and Origin of Fiords, by J. W. Gregory, F.R.S. London : 
John Murray. Pp. xvi + 542, 16s. net. In addition to his ordinary 
professional duties, and lectures and papers and addresses innumerable, 
Professor Gregory seems to find time to prepare substantial monographs 
on various phases of geological research. His ‘ Great Rift Valiev,' and 
' The Dead Heart of Australia,’ are perhaps the best-known of his many 
contributions. Those who know him will admire his thoroughness. Xo 
matter what subject he takes in hand (and their variety is marvellous), 
when he has thrashed it out his decision may usually be safely said to 
be the ‘ last word.’ His Fiord volume is really a sequel to his ‘ Great 
Rift Valley.’ Professor Gregory will not agree that fiords are the result 
of glacial action nor of other ordinarv erosive agencies. ‘ Their plan 
resembles that of cracks in a fractured sheet of brittle material, and does 
not agree with that of systems of valleys cut bv rivers or glaciers. Fiords 
are restricted to plateaus, which are composed of firm and usually old 
rocks, and to districts which are on the borders of sunken areas. All 
the fiord-areas have been affected by a similar succession of earth move- 
ments.’ He considers that the fact that most of the fiords are in colder 
regions of the earth is a coincidence due to the polar areas having been 
affected by greater oscillations than the equatorial zone. It is possible 
there may be differences of opinion on the point. However, as evidence 
of Professor Gregory’s methods, not only has he visited Norway and 
Spitsbergen — countries usually looked upon as the home of the fiord — 
but he has been to Brittany, the West Indies, New Zealand, the Baltic, 
British Columbia, and Dalmatia, besides several Scottish localities. 
In addition to his personal observations Professor Gregorv has mastered 
the literature on the subject — a bibliography of which is given — and 
which would alone have been enough for most people ! Whether Pro- 
fessor Gregory’s ideas receive universal acceptance or not — and he 
always has a strong following — all will admit that his Fiord book is a 
distinct and welcome addition to geological and geographical science. 
It is well illustrated and well indexed. 
1914 Mar. 1. 
