How does Mrs. Dean describe her history at Thrushcross Grange in Chapter 4?

Mrs. Dean tells Lockwood she has lived at the Grange for eighteen years, since her mistress married and moved into the house; when her mistress died, she remained as housekeeper. Mrs. Dean tells Mr. Lockwood that Mrs. Heathcliff's maiden name was Catherine Linton, and her father was Mrs. Dean's late master.