Simplify the following text for a Grade 8 native English-speaking person.
Original: The Western Grey is not found in the tropical north or the fertile south-east of Australia , and the Eastern Grey does not extend beyond the NSW-South Australia border , but the two species are both common in the Murray-Darling Basin area .
Simplified: The Western Grey is not found in the tropical north or the fertile south-east of Australia . The Eastern Grey is not found over the NSW-South Australia border , but the two species are both common in the Murray-Darling Basin area .