Simplify the following text for a Grade 7 native English-speaking person.
Original: The Aleutian Islands ( É Ë luË Ê É n ; possibly from Chukchi aliat , `` island '' ) are a chain of more than 300 small volcanic islands , forming part of the Aleutian Arc in the Northern Pacific Ocean , occupying an area of 6,821 sq mi ( 17,666 kmÂ ) and extending about 1200 m westward from the Alaska Peninsula toward the Kamchatka Peninsula thus marking a line between the Bering Sea and the Pacific Gulf of Alaska .
Simplified: The Aleutian Islands ( É Ë luË Ê É n ; possibly from Chukchi aliat , `` island '' ) are a chain of more than 300 small volcanic islands . They are in the Northern Pacific Ocean .