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Millstone grit topsoil below {{convert|275|m|ft|abbr=on|0}} has a [[soil ph]] that is almost neutral, ph 6 to 7, and so grows good grazing. But above {{convert|275|m|ft|abbr=on|0}} it is acidic, ph 2 to 4, and so can grow only [[bracken]], [[Ericaceae|heather]], [[sphagnum]], and coarse grasses<ref >{{cite book |title=The Yorkshire Dales: South and West|last=Kelsall|first= Dennis |coauthors=Jan Kelsall |year=2008 |publisher=Cicerone |location= Milnthorpe |isbn=978-1-85284-45-1}}{{rp|26}}</ref>.