The appalachians are very, very old.. and they start in the ozarks, which got cut off from the main part of the chain by the mississippi. (all of this is from general reading and US geological Info survey(GIS)-) In the US, they extendt to Maine, but continue onto cananda -- the same coal that is mined in West Virgina, is mined in Nova Scotia, (and Canada has its own 'coal miners daughter' in Anne Murray) but they don't end in canada.
Long, long ago, the north american main land was connected to europe (in one of the phases of what is now called Gai) and the same geological structures that make for coal mines in WV, also exist in Wales and Scotland. The geological layers there, mimic the ones in the appalachians, (with the same rich coal layer) so it seem geologically, ireland, Wales, Cornwall and Scotland, where once part of the same land mass as east coast of North America.. but every 50 miles or so, the mountains change names.
So far
(Ozark)
Smokey
Blue Ridge
Kittatinny
Poconos
Catskills
Taconic
(that is more or less, going from south west to North east)
i know at least 5 other local names.. (Massachusets, NH, Pennsylvanian, --if you count foot hills (like the Ramapo or Watchangs,(Whit, you for got the Watchangs!-- i was leaving the Taconic's for some one up state NY!)
they are much more eroded in the south that in the north, the mountains of NY are hoo-hum, but the moutains of Nova Scotia are mountains and i under stand to Canadians, the mountains of Nova Scotia are hills compared to New Brunswick..
Even in NH (where are you Wow?) the Appalachins are mountains by any ones estimation (snow covered in summer, steep rocky crags, highest point of elevation on the east coast, worst weather (some say world, but at least in NA).
One of the continuing features is the Serpentine (which Dr Bill above give more details about.) Anthrocite coal is an other. the fosiles in shale between the layers of coal also are very similar.
and finally WW, the appalachian trail starts in Georgia. Parts of West Virginia are called Appalachia, but the but the Appalachian mountains are a huge, old, eroded chain.. and not limited to West Virginia. they shape my land scape (well 50 miles away) too.
OP
