Inner range consists of Tribeč, Žiar, Veľká Fatra, Chočské vrchy, Ďumbier part of Nízke Tatry and massif of Smrekovica in the Branisko.

The Tatra-Fatra Belt consists of Tatric alpine crystalline basement and its autochthonous sedimentary cover, over which the Subtatric nappes (Fatric and Hronic) were thrust.

The basement of the core mountains is formed by the Tatric Unit, which is composed of dominantly hercynian metamorphic and igneous rocks and locally also a sedimentary cover of various thickness.

In the Upper Cretaceous area of Tatric Unit, was affected by Eo-Alpine of Alpine Orogeny, that caused movement of large masses of rocks to the North and Northeast.

Surface occurrences of Fatric basement remained only as a remnants in the northern part of Veporic Veľký Bok Unit and few other areas.

In the Neogene, further orogene movement in the external part of Carpathian arc caused formation of back-arc Pannonian Basin.