442 
NATURE 
[Sepz. 9, 1886 
Chepstow Meteorological Observato: 
Magnetic Observations aes rth ep ae 4.0 
Electric Standards... 20 aoe an Si ee 5° 
B—Chemistry 
Silent Discharge of Electricity ae ese rs ce 20 
Absorption Spectra =. 40 
Translation of Foreign Records me 5 
Nature of Solution oon 20 
Influence of Silicon on Steel 30 
C—Geology 
Volcanic Phenomena of Vesuvius ... acs aoc eae 720 
Volcanic Phenomena of Japan BG ee ae wee 50 
Exploration of Cae Gwyn Cave... a0 op ZO 
Erratic Blocks ABD aes ee ae ec cod =e) 
Fossil Phyllopoda os aos oo con eee 20 
Carboniferous Flora of Halifa: nee Bes A er 25 
Microscopic Structure of the Rocks of Anglesey ... 7 10 
Eocene Beds, Isle of Wight awe as oc ae 20 
Circulation of Underground Waters eee 500 mee 5 
Erosion of Sea Coasts e. ay Wes ee oe 15 
‘Manure ” Gravels of Wexford ... oe sts eee TO 
Provincial Museum Reports ... tee 5 
: D—Biology 
Lymphatic System... one Sp otc m0 eee 25 
Naples Zoological Station ... Res on eas een LOO 
Plymouth Biological Station ane aes con ae £50 
Granton Biological Station ... va Soe wee mes 75 
Zoological Record... eee Fido cn tae et #100 
Flora of China nee wai aes an ae eee! 75 
Flora and Fauna of the Cameroons te bey noe 75 
Migration of Birds ... ae we not gt ae 30 
British Marine Area ... a ate = sod 5 
E—Geography 
Batho-Hypsographical Map ... SC ws “0 ces 5 
Depth of Permanently Frozen Soil ... sae a ae 5 
F—Economic Science and Statistics 
Regulation of Wages... 
. or06 . 10 
H—Anthropology 
Prehistoric Races, Greek Islands 20 
British Barrows ase ox ae «20 
North-Western Tribes of Canada 4 50 
Racial Photographs (Egyptian) so co ae 20 
Anthropological Notes and Queries Bo O08 mom IO 
Total ... 41300 
SECTION C 
GEOLOGY 
OPENING ADDRESS BY PrRor, T. G. BonnEy, D.Sc., LL.D., 
F.R.S., F.S.A., F.G.S., PRESIDENT OF THE SECTION 
T HAVE felt it a great honour and an especial pleasure to be 
asked to preside at the meeting of Section C in Birmingham. 
A great honour, because of the repute of my predecessors ; an 
especial pleasure, because, as born in the Midlands, I am 
naturally proud of the Midland metropolis, its intellectual 
activity, and its commercial enterprise. Besides this, there are 
few towns in England where I number more friends of kindred 
tastes than in Birmingham, Geology especially seems to thrive 
in this district, and little wonder when you reckon among your 
residents, in addition to a host of other workers, such leaders as 
Crosskey, malleus erraticorum, Allport, who taught me how to 
work with the microscope, and Lapworth, to whose genius my 
duller mind is under constant obligation. 
The addresses delivered at the annual meetings of the British 
Association afford a convenient opportunity for what may be 
termed stock-taking in some branch of science which has espe- 
cially attracted the attention of the author ; for a brief review 
of past progress ; for a glance forward over the rich fields which 
still await exploration. We may compare ourselves to pioneers 
in a land as yet imperfectly known, the resources of which are 
only beginning to be developed. Taking our stand upon some 
vantage-ground at the border of the clearings, we glance forward 
over plains as yet untrodden, over forests as yet untracked, to 
consider in what directions and by what methods of investiga- 
tion new lands can be won through peaceful conquest, new 
treasures added to the world’s intellectual wealth. 
I purpose, then, on the present occasion to offera few remarks 
upon a branch of geological investigation which appears to me 
one rich in promise for future workers. The key-note of my 
address might be conveyed in the following sentence: ‘‘The 
application of microscopic analysis to discovering the physical 
geography of bygone ages.”” The ultimate aim of geological 
researches is obtaining answers, in the widest and fullest sense, 
to these two problems in the history of our globe—the evolution 
of life upon it, and the evolution of its physical features. In 
the former a host of labourers, before and since the epoch of 
Darwin’s great book, have been employed in collecting and 
co-ordinating facts, and in framing hypotheses by scientific 
induction. In the latter the workers are fewer, but the results 
obtained are neither small nor unhopeful. In the past genera- 
tion, men like Godwin-Austen pointed out the principles of 
work and gathered no small harvest, but in the present the 
application of the microscope to the investigation of rock-struc- 
ture has facilitated research by furnishing us with an instrument 
of precision ; this, by disclosing to us the more minute mineral 
composition and structural peculiarities of rocks, enables us to 
recognise fragments, and sometimes even to determine the source 
of the smaller constituents in a composite clastic rock. The 
microscope, in short, enables us to declare an identity where 
formerly only a likeness could be asserted, to augment largely 
in all cases the probabilities for or against a particular hypo- 
thesis, and to substitute in many a demonstration for a 
conjecture. 
Once for all, Task you to bear in mind that this address is 
mainly a recital of other men’s work, so that I shall not need to 
interrupt its continuity by remarks as to the original observers. 
The subject is, indeed, one to which I have paid some attention, 
but I can only call myself a humble follower of such men as 
Godwin-Austen, ‘the physical geographer of bygone periods,” 
and Sorby, who was the first to apply the microscope to similar 
problems, and to whom in this class of investigation we may 
apply the well-known saying, Wihil tetigit guod non ornavit. 
With the deepest gratitude also I acknowlege the loan or the 
gift of specimens from Drs. Hicks and Callaway, from Messrs. 
Howard Fox, Somervail, Shipman, Gresley, Houghton, Marr, 
Teall, and J. A. Phillips, from Profs. Lapworth and Judd. 
Through their liberality I have had the opportunity of examining 
for myself the greater part of the materials which have already 
been described in the principal geological periodicals, and of 
adding many new slides to my own collection. 
The nature of the materials of grits and sandstones has been 
so admirably treated by Dr. Sorby in his presidential address to 
the Geological Society for 1881 that I may pass briefly over this 
part of the subject. I will, however, add a few details in the 
hope of placing more clearly before you the data of the problems 
which are presented to us. In order to exemplify the size of the 
fragments with which we have to deal, I have made rough 
estimates of the diameters of the constituent grains in a series of © 
quartzose rocks. Sometimes there is much variability, but very 
commonly the majority of the grains are tolerably uniform, both 
in size and shape. Ina slide from the Lickey quartzite, exposed 
in the railway cutting at Frankley Beeches, grains, often well 
rolled, ranging from *02” to ‘03’ are very common. Ina speci- 
men of Hartshill quartzite, they range from ‘o1” to *03”, 
but the most common size is a little under ‘025’. In a 
quartzite from west of Rushton (Wrekin) a good many grains 
range from ‘03” to '05.” In two speciments of quartzite (white 
and pale grey) from near Loch Maree, the grains commonly vary 
a little on either side of ‘02’, while in a specimen of the 
“fucoidal quartzite” (mouth of Glen Logan) much greater 
variety is exhibited, a good deal of the material being about ‘or’ 
in diameter, but with many scattered grains up to ‘03”. The 
grains in a pale grey quartzite from the Bunter beds at the north 
side of Cannock Chase range from about ‘or” to ‘or5”, and are 
very uniform. In aliver-coloured quartzite from the same locality 
they are about as long, but narrower and sharply angular in 
form. These will serve as examples of what we may call an 
average, moderately fine grit or sandstone. It is my impression 
that in a very large number of ordinary sandstones most of the 
grains range from about one to three hundredths of an inch. 
In rocks, however, to which most persons would apply the 
epithet ‘‘rather coarse-grained,” fragments of a tenth of an 
inch or more in diameter are common. 
It is extremely difficult to give, in general terms, an estimate 
oe Eg at 
