There is also this geological divide with the Fulda-Haune Tableland, which lies in front of the Knüll to the northeast. Between them is the Großenlüder-Lauterbacher Graben. By contrast, in the north, the vulcanite does not end until it reaches the adjacent North Vogelsberg Foreland, i.e. outside the actual Vogelsberg. Even the Anterior Vogelsberg which lies outside the latter region still has large areas of basaltic rock. To the west the basalt zone reaches far into the gently rolling lowlands of the Wetterau, this depression lies alongside the middle and lower reaches of the Horloff river.