208 
secretary's report, 1906. 
Bristol zones were laid down must have lapped round 9 land 
area which was submerged later by the sea in which the fauna 
of the upper zones lived. 
In Yorkshire, and the north, these upper beds of the Lower 
Carboniferous were found in two forms — one, called by Professor 
Philhps the Yoredale series, which consisted of a series of hme- 
stones, ccmparatively thin, separated by shales, and southwards 
represented by a great thickness of pure white limestone, which 
included the same zonal series. Dr. Hind explained this change 
as due to a great river from the north-east, which spread its 
muddy sediment ever northern England, the fringe of whose 
delta thinned out south of Settle. At intervals the corals and 
shells which luxuriated in the clear sea to the south, were able 
to encroach on the delta in times of lessened sedimentation. 
Thus the pure limestones of the southern area were forming 
at the sari)e time as the Yoredales of the northern area. 
A band of shales and limestones, the Pendleside series^ 
was found stretching east and west, from Pendle Hill, where 
they attain a thickness of 1,000 feet, across Yoi'kshire, until 
hidden by the newer rocks, and reappearing in Belgium, and 
Germany. These would need for their explanation another 
river, probably flowing from the east. 
Dr. Hind's lecture was followed by a valuable discussion, 
in which reference was made to the interesting results obtained 
in zoning the Coal Measures of Staffordshire. Certain marine 
bands and bands containing freshwater shells being found at 
definite horizons, the position of which enabled mining engineers 
to calculate with great nicety the position of related coal- 
seams in a faulted area. Similar bands had been found in the 
Yorkshire Coal Measures, and it was urged that additional 
attention should be paid to these zones, which would be of 
considerable practical use to the mining engineer. 
On Saturday, April 14th, the party visited the old limestone 
quarries on Greenhow Hill, from which a plentiful supply of 
corals was obtained. Thence the drive was continued to Dibbles 
Bridge, where similar Yoredale limestones were examined. 
A traverse was then made across Appletreewick pastures to the 
