You find the Plume Fossil in the Relic Castle. It is on the first floor on the other side of a sand pit, given to you by a girl near the stairs in the bottom left corner, who will give you a choice between the Shell Fossil (Tirtouga) and the Plume Fossil (Archen). Also, a tip. To get across the sand pit, walk, don't run. Running will make you sink down the hole into a lower floor. Take the fossil to the museum in Narcene City to get the fossil revived.
You must revive its fossil.
Archen evolves into Archopes at level 37 in Pokemon Black, hope this helps :)
i think you can only find it in Pokemon black if you have white like i do tuff numbs.
Archen evolves into Archeops at Lv. 37.
37
Yes. Al you need to do is catch either one of the pokemon mentioned, for example Archen, then get a friend to trade from black -> black or white -> black with the other pokemon (in this case Tirtouga) to you.
archeops at lvl 37
Cover Fossil is Tirtouga. Plume Fossil is Archen.
Zorua,reshiram,tirtouga,archen
yes. it evolves into archeops.
There is a lady with a backpack on she gives you either a plume fossil(Archen) or a cover fossil(tirtouga)
Tirtouga from the Cover fossil, and Archen from the Plume fossil.