I've found it (on the web, i.e.):

"By the road end of Bluestone Lane was a thatched cottage, since rebuilt. A little further up Bluestone Lane, 20 yards or so on the south side of the cottage was a large blue boulder scored ,it is said by ice bergs in the ice age. The Bluestone gave its name to the road and was a well known signpost in olden days. The Bluestone was removed during road repairs and taken by the council to a tip. A resident of Bluestone Lane , Mr. H. Rigby persuaded ,the council to bring it back and it now lies in the front garden of his bungalow, which was originally Ash Farm."

From:

http://www.mawdesley-village.co.uk/historymb2.html#Chap2

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