to get the fossils of Cradily and Armaldo (i forgot the unevolved names) you can find them in the top-right corner in the desert north of mauville. *you need Go-Goggles for this*
The Claw fossil
Anorith and Lileep.
In the dessert
there are different Pokemon in it
IT is in the mountain where you fight a guy and you get to choose which fossil to get
in mt moon
it is in the top right of the desert. you can choose between it and the claw fossil
you can revive it to get an anorith. the root fossil will give you lileep.
You can get ditto in Pokemon ruby by beating the Pokemon league then going to the cave the fossil maniac is digging he will be finished digging and he will say to be careful that there are Pokemon in there the Pokemon in there are ditto.
it is right side
Lilleep comes from it, which evolves into a Cradily. The other fossil has an Anorith, which evolves into an Armaldo. Good luck, Trainer!
I have Pokemon Sapphire, but it's the same thing in both games. There are two fossils, one is the root fossil and one is the claw fossil. The root fossil will get you a Lileep (which then evolves into a Cradily at lvl40) and the claw fossil will get you an Anorith (which also evolves at lvl40 to give you an Armaldo). Hope that helps!!