82 NORTH AMERICA/Northern Appalachians Figure Tectonostratigraphic map of the Northern Appalachians Zonal divisions are principally based on sharp contrasts in Lower Palaeozoic geology; the main belts of Siluro Devonian sedimentary and volcanic rocks are outlined in white The major structures and principal orogenic events responsible for their formation are indicated by line patterns The extension of structures off the land is based on geophysical interpretation and well data AAT, Annieopsquotch accretionary tract; BBCL, Baie Verte Brompton Cameron Line; BOI, Bay of Islands Ophiolite; BVOT, Baie Verte Oceanic Tract; CCF, Cobequid Chedabucto fault; DBLOL, Dog Bay Liberty Orrington Line; ESZ, Exploits Subzone; GZ, Gander Zone; HZ, Humber Zone; NDSZ, Notre Dame Subzone; NR, New River Belt; RIL, Red Indian Line; PVA, Popelogan Victoria Arc; TEB, Tetagouche Exploits back arc Basin; TM, Thetford Mines Ophiolite; VA, Victoria Arc