Limestone Clints & Grykes walk - Lancashire Wildlife

13 Upon reaching the tarmac drive turnright and continue downhill for 400mto Grisedale Farm. Continue past thefarm through the gates to the reedbeds of Leighton Moss.After the last ice age, the Leighton Mossvalley floor, known as a ‘polje’, would havebeen lower and would haveexperienced periodic flooding of the seadepositing a layer of impervious clay overthe limestone valley floor. At the sametime, water flowing into the valley fromthe surrounding land was unable to drainaway and a large area of marsh developedsimilar to salt marsh and mudflats.The gradual rise of the land since the lastice age and the intervention of man haveproduced the landscape you see today.Perhaps the most dramatic change toLeighton Moss occurredin 1830.A substantial embankment(1km in length)was constructed acrossthe valley from the footof Heald Brow to thebase of Warton Crag.The Gillow family ofMarsh HarrierPhoto:David MowerLeighton Hall installedan engine with a paddlewheel pump near CragFoot. This pump drained water frombehind the embankment to provide landfor growing crops.Whilst the pump was in operation, the soilproved to be exceptionally fertile and largequantities of crops were produced.The valley earned the title, ‘Golden Vale’.The tall chimney of Crag Foot is the onlysurviving landmark. The pump becameredundant in 1917 because of difficultiesin finding fuel supplies. In the past 2 yearsthe moss has undergone dredging work ofa different nature to deepen the lagoonsand channels to benefit wildlife,in particular the bittern.Crag FootChimneyReed BuntingPhoto:Mike Richardsrspb-images.comBittern © RSPB14 After 800m ‘the causeway’ joinsthe road once again. Bear left and headback towards RSPB visitor centre and therailway station.This leaflet has been produced by the:Arnside/Silverdale Area of Outstanding Natural BeautyThe Old Station Building, Arnside, Carnforth LA5 0HGTel: 01524 761034email: info@arnsidesilverdaleaonb.org.ukwww.arnsidesilverdaleaonb.org.ukAreaArnside andof Outstandin gSilverdaleBeautyNatural