St. Catherine's Hill is a sandstone cliff, rising above the Wey, a mile south of Guildford, and nigh unto the wood below "the long backs of the bushless downs" where once Sir Lancelot was tended by Elaine. It is a thirteenth century chapel that stands there, ruined long ago by the Protestants ; but children play there still, and outside the chapel, in October, Cattern's Fair is held, and cattern cakes are sold and eaten, and gipsies bring thither their brown women and their wiles.
St. Martha's, in sight of which I write this, is twin with St. Catherine's. The two chapels were built (saith the story) by two giant sisters, who had but one hammer between them, and tossed it from the one hill to the other as either needed it in building.
A. J. M.
From Notes and Queries, August 14th 1886.
About 1894, schoolchildren used to take bottles with sugar or treacle to fill, and drink in company, at the spring which flowed out at the foot of St Catherine's Hill, Guildford (site of a chapel and an ancient horse fair), on the side nearest the river.
Holy Wells in Surrey
Folklore > Vol. 64, No. 2 (Jun., 1953), p. 350
I have only found some snippets online about the archaeology: the hill has produced mesolithic finds, a bronze axe, disc and ornament.
From the London Review, 1863. You wouldn't believe what the riff-raff are getting up to at St Catherine's Hill on 'Tap-Up Sunday'. Four hundred of Guildford's 'lowest inhabitants' were there causing havoc apparently.
The 1898 edition of Brewer's 'Dictionary of Phrase and Fable' points at why: The Sunday preceding the fair held on the 2nd October, on St. Catherine's Hill, near Guildford, and so called because any person, with or without a licence, may open a "tap," or sell beer on the hill for that one day.