Rajmahal hills of Jharkhand is the type area of this province. Multiple layers of solidified lava made 608 m(1,995 ft) thick Rajmahal hill. The chief characteristic of the geology and rocks of India arid-zone is noticed inits remarkable succession of pre-Cambrian rocks which go far down towards the base of the Archaean. This sequence commences for the Bundelkhand gneiss,which is one of the oldest granites exposed any whereupon the earth' surface.