Chapter 18.

If you are referring to chapter 18, Cathy appears to display more Linton characteristics than Earnshaw ones, her desire to explore the wilderness outside of the Grange's park links her strongly to the wild, Wuthering Heights clan. Her sauciness also reminds the reader of her mother, as does her aristocratic unwillingness to be related to Hareton (just as Catherine thought it would degrade her to marry Heathcliff, who was at the time very much like Hareton).