17 
LIBRARY RULES. 
1.—The Library will be open daily, except on Holidays, 
from 1oa.m. to 4p.m.; and from 6 p.m. to 9-30 p.m. on the 
evenings when the Societies meet. 
».—As the Library is intended for purposes of study and 
reference, Members are expected to abstain from conversa- 
tion which may be disturbing to other readers. 
3.—Members are requested not to replace Books on the 
shelves, but to give them to the Attendant for replacement. 
4.—No Periodicals belonging to either Society are to be 
taken out of the Library. 
5.—The Books belonging to the Archzological Society 
are intended as books of reference, and must not be taken 
away. 
6.—Books belonging to the Society of Natural Science 
may, with certain exceptions, be taken out by Members of 
the Society, under the Rules of the Society. A receipt must 
be given to the Librarian for all Books so borrowed. 
7.—Persons who are not Members of either Society, desir- 
ing to use the Library, must present a letter of introduction 
from a Member, endorsed by the Secretary, or President, of 
the particular Society whose Books they wish to consult; such 
order to be available for one week only. 

NOTES ON WYNNE AND CAMBRIAN SLATE-QUARRIES, 
GLYN CEIRIOG, 
By Mr. Wm. SHONE, F.G.S. 
The following particulars were given to me on 29th June, 1904, by 
F. E. Rooper, Esq., F.G.S., and they are of great interest with regard to 
the Orientation of the Mountain Systems of Wales. The system of the 
Longmynd is N. 25° E. (see * Prestwich’s Geology,’’ Vol. I., p. 292) :— 
Top of Rock—‘ Dirty Bed ”_ useless Pays Leek 
Beneath the above the Slate Vein... eg LO Pap 
Run of Slate Vein ae oe ste es 71° W.ofN. 
Pillaring .. 4/ aie as ale .. I°K.OfN. 
Dip of Vein ee . ee ee .. 42° E. of N. 
Dipping .. He is ee ee Ao) ty 
Cleavage .. ne ee oe eo oe. 42° E.of N. 
Dipping .. ee ee ee .e mene), - 
vj 
