132 
THE LICHEN FLORA OF HARDEN BECK 
VALLEY: 
THOMAS HEBDEN. 
AN account of the Lichen Flora of a portion of South-West 
Yorkshire (V.C. 63) may be useful as a comparison with that 
of V.C. 59 and V.C. 63 described by Messrs. Wheldon and 
Travis.* The district I am best acquainted with in V.C. 63. 
is that of Harden Beck Valley, which is within about ten miles 
from V.C. 59, and very similar in geological, climatic and 
industrial conditions. 
Harden Beck Valley may be compared to a little green 
oasis surrounded by a zone of constantly increasing industrial 
activity, and nowhere more than four miles from Bradford, 
Shipley, Saltaire, Bingley, Keighley, Worth Valley, Oxenhope, 
Denholme and Thornton, thus completing the circle of smoke- 
producing conditions, the only free portion being to the S.W., 
but even from there the smoke cloud from the Calder Valley 
and Lancashire often reaches this district. 
Harden Beck Valley itself contains the four villages of 
Harden, Wilsden, Cullingworth and Denholme, each with its 
factories and cottage chimneys, adding to the already drifting 
smoke-cloud from the surrounding district. 
Geologically, the eastern side of the valley is the outlying 
portions of the Lower Coal Measures ; the western side being 
Millstone grit. The summits of the hills, capped with isolated 
blocks of rough sandstone, often peat covered, rising to an 
elevation averaging 800 to 1,000 feet above sea level; the 
valley being nowhere more than three to four miles wide from 
the summits of the watershed. The lower third of the Valley 
is well wooded, oak and birch predominating. Several high- 
ways intersect the valley, mostly limestone repaired, which 
encourage calcicole species, yielding aliens of very interesting 
character. All the Lichens found in the district are in a more 
or less depauperate condition, mostly dwarfed and so much 
smoke-begrimed that it is a difficulty to recognise some species. 
I have never yet succeeded in finding a single corticole specimen 
except an occasional Lecanora varia or Parmelia physodes. 
In comparing results with that of Messrs. Wheldon and 
Travis’s list, it is necessary to eliminate their sea-side gatherings 
and also their collection from the district north-west of Colne, 
owing to the geological difference in both cases. 
The species in the following list have all been collected 
within a radius of about ten square miles, nearly every square 

*¢List of the Lichen Flora of South Lancashire’ (V.C. 59 Watson), 
Linnean Society’s Journal, Vol. XLIII., October, 1915. 
Naturalist,. 
