The mountain is steep towards south and east, and there is a subtle change in the rock layers between the sparagmite foundation and the summit which consists of the much harder gabbro rock. The summit is one of the southernmost outcrops of gabbro in the vicinity, and Bitihorn is therefore significantly higher than its neighbors to the south and east. Underneath the sparagmite layer, lies a layer of extremely nutritious slate, called phyllite. That layer and its subsequent plant cover is the reason for the many mountain pastures in the area.