is a fossil that you get in brock's city on the top of it, is a museum there you use cut and you will get the fossil in the museum

none of them coz helix is omanite and dome is kabuto to get aerodactyle u need 2 get cut and use it by the back of the museum go in talk to all the people and one of them gives u the amber then fly to cinnabar island and give it to the proffessor in the second room across in the lab walk out of the room and walk back in and talk to the man again and he gives u an aerodactyle (make sure u have room in ur party)

you dont get aerodactly at mt moon you get him from some guy at pewter city, the house next to the musem

i love the classics

Aerodactyl can be found at the museum its in the amber thingi & the fossils in mt. Moon r
helix: omanyte dome: kabuto (i prefer kabuto)