174 
PETROLOGY OF LOCAL PEBBLES. 
Aug. 1889. 
to visitors according to the order in which their application 
for tickets is received. 
For those who prefer it, or who cannot be entertained, 
information concerning lodgings and hotels may be had on 
application to the Secretary. 
The Secretary will be glad to receive communications from 
any members who have interesting exhibits to show at the 
conversazione. 
H. M. J. Underhill, 
Secretary of Oxford Natural History Society. 
7, High Street, Oxford. 
THE PETROLOGY OF OUR LOCAL PEBBLES.* 
BY T. H. WALLER, B.A., B.SC. 
The great pebble beds of the district round Birmingham 
are probably familiar to all the members of this Society, to 
many of them far more so than they are to myself. My 
opportunities for collecting specimens from them have been 
very few and far between, and as I am not likely to be able to 
give much more time and attention to the subject in the future 
than in the past, it seemed as if a sort of interim report on the 
petrology of the pebbles might be of service in stimulating 
to a closer study of the deposits some who can give more 
time to the matter than is possible for myself. 
At any rate, whatever we know of the gravel and pebble 
pits, and the occurrence of the pebbles in situ, we all know 
the general appearance of the component pebbles. Many 
of us no doubt have examined them a little more closely, and 
have observed that by far the larger number are composed of 
some form of quartzite, and it is some of these quartzite 
pebbles that have furnished to the minute search of several 
indefatigable workers amongst us (Messrs. Harrison, Evans, 
and others) those rare and proportionably valuable fossils to 
which we must look to indicate the geological horizon of 
the rock masses from which the fragments were torn, which, 
after the rough knocking about which has rounded them, and 
smoothed—indeed, in many cases almost polished—them, 
went to make up the great formation of the Bunter pebble 
beds. 
Professor Lapworth has indicated, in the lecture to which 
we listened with such pleasure and profit some six months 
* Read before the Birmingham Natural History and Microscopical 
Society, 19th March, 1889. 
