Basement is a type of Place. Valley is a type of Place. you are likely to find Valley in/at/on Continent. Continent is related to Global. 
Retain is the opposite of Slip. Slip is related to Ground. 
Basement --IsA--> Place <--IsA-- Valley --AtLocation--> Continent <--RelatedTo--> Global 
Retain <--Antonym--> Slip <--RelatedTo--> Ground 