A registered National Natural Landmark since 1969 , the Glens Natural Area is the main scenic attraction in the park .
A registered National Natural Landmark since 1969 , the Glens Natural Area covers 2,845 acres ( 1,151 ha ) .
A registered National Natural Landmark since 1969 , the Glens Natural Area is the main scenic attraction in the park and covers 2,845 acres ( 1,151 ha ) .