After talking to him there he'll be back in Silph Co. near the entrance.
:~)
You have to have the Engnima stone.
In Soul Silver Steven is in the Pewter City Museum talking about rocks :/
Pewter Mueseum
You don't but after you defeat red at mt silver you can receive a hoen starter from him in silph co in saffron city then after you talk to him in the pewter museum of science you can trade your forretress for his beldum
you meet steven for the second time at the museum in Pewter City.
He goes to the museum which is in pewter city.
the fossil person is behind the desk in the pewter museum
You find him at the Pewter city meuseam.
There is no tower in Pewter City. Pewter City only contains one spot of interest, which is the Museum. There is no tower in existence there.
i'm not sure in soulsilver but in heartgold after seeing him in the pewter museum you can trade him at silph co
In the Pokemon series you can revive fossils into rare Pokemon. In Pearl you can do this at the coal museum.
It is in kanto after you beat the Champion. Hope this helps? Thanks.