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explained that the whole series of the Millstone Grit was 
represented in the district the party was passing through. The 
first series cropped out at Hoghton Tower, another series—the 
Haslingden flags—came into view between Woodcock Hill and 
Alum Scar, while the third great series was represented by the 
cliff of the Scar itself, under which was the shale from which 
the alum was extracted, and which gave the name to the place. 
The Scar itself, which was the object of the afternoon’s visit, 
is situated in the ravine down which a little stream, the Arley 
brook, a tributary of the Darwen, flows. Each side is covered 
with a rich growth of trees; and the debris from the mines, 
(which up to the close of the last century had been worked at 
intervals for about 150 years) is now clothed with abundant 
vegetation. It was not difficult to discover the particular portion 
of the mine which was last worked, the road to it still bemg in 
existence, but the works have long been abandoned. Once only 
in their history have they paid as a commercial speculation, and 
now, in consequence of the competition and the easier way in 
which the alum is extracted in mines where the geological con- 
ditions are more favourable, they have had to be finally abandoned. 
It has been alleged that one reason for the failure was on account 
of the immense beds of millstone grit it was necessary to pierce, 
prior to meeting with the shale from which the alum is taken. 
When they were in operation the alum was taken down to 
Walton on the river Darwen, and stored in a warehouse close to 
the Ribble, whence it was removed for exportation. The alum 
was extracted from the stone by boiling. During the whole of 
the pleasant ramble Mr. Shortt gave most interesting information 
not only respecting the geology of the district, but the botany, 
as well as the archeology, and the members of the party expressed 
to him their obligations for the instructive afternoon they had 
spent under his kind and careful guidance. A large yellow under- 
wing, several other small moths, and also a few specimens of oak 
fern and beech fern were brought away by members of the party. 
HECKENHURST AND CANT CLOUGH RESERVOIR 
WORKS. July 25th, 1885. 
Directors— 
WILLIAM WILLIAMSON and J. E.STAFFORD, A.M.1LC.E. 
The party drove first to Heckenhurst Reservoir in order to 
note the works which are in progress to make it watertight. This 
reservoir was constructed about the year 1850, for the Burnley 
Improvement Commissioners, Mr. C. E. Cawley being the 
Engineer. It never was perfectly watertight. The reservoir 
was however used, its supply being obtained from Holden Clough 
