GEOLOGY AND MINERAL RESOURCES
Extent of Geological Record.— Although the main part of the Panjab plain is covered by a mantle of comparatively recent alluvium, the provinces described in this book display a more complete record of Indian geological history than any other similar area in the country. The variety is so great that no systematic or sufficient description could be attempted in a short chapter, and it is not possible, therefore, to do more in these few pages than give brief sketches of the patches of unusual interest.
Aravalli System.— In the southern and south-eastern districts of the Panjab there are exposures of highly folded and metamorphosed rocks which belong to the most ancient formations in India. These occupy the northern end of the Aravalli hills, which form but a relic of what must have been at one time a great mountain range, stretching roughly south-south-west through Rajputana into the Bombay Presidency. The northern ribs of the Aravalli series disappear beneath alluvial cover in the Delhi district, but the rocks still underlie the plains to the west and north-west, their presence being revealed by the small promontories that peep through the alluvium near the Chenab river, standing up as small hills near Chiniot in the Shahpur, Jhang, and Lyallpur districts.