Intensive study began in the foothills of the South – western Himalayas. These constitute the Siwaliks and the Potwar plateau. The latter is a part of ancient Pan Canada, drained by the Sindhu, Sohan, Jhelum, Ravi, Sutlej, and Beas; it includes Rawalpindi and other districts of Western Punjab.

        Man’s presence was believed to have been first noticed in the Boulder Conglomerate which forms the topmost surface in the Sindhu, Shaan and other rivers. During the Second Ice Age in the Kashmir valley, the Potwar plateau experienced very heavy rain and the rivers carried away boulders. This helped to form the Boulder Conglomerate.

In this formation were found huge flakes and split pebbles of quartzite. Some of these were regarded as artifacts, as they showed traces of chipping on the side.

To distinguish this industry from the later industries, it was called pre-Sohan, but now it is thought that there are no clear sings of man’s work on these flakes and pebbles. We may, therefore, say that man did not exist during the Second Ice Age.

        Both in the Kashmir valley and the Punjab plains genial climate due to interglacial conditions seems to have prevailed. Under such favorable climatic conditions, two distinct types of stone tools have been found: the handaxe and pebble tools, and a few flake tools. The latter are so atypical and different from the former that the industry typified by them is called Chopper – Chopping or Sohan Industry.       

When the climate changed, Kashmir was under a mantle or ice for the third time. As a Result, fine silt called ‘loess’ was carried over great height. These deposits formed a second terrace (T2) in the Sindhu and Sohan valleys.

         Man was present at these times and witnessed profound changes on the surface of the land. His tools differ to some extent from those previously found in the Sohan. These occur in the basal Potwar gravel and in the lower 6m. of the silt. But the cores and flakes show some previous preparation and recall not only the “Levalloisian technique” but also a change in the mode of life, when flakes were preferred for cutting up animals such as Horse, Bison, Camel and Wolf, the remains of which occur in the Potwar ‘loess’. Anyway, stratigraphically, climatically, and culturally there is a distinct change.

        The entire region once again underwent a change. Interglacial conditions reappeared and a new terrace (T3) was formed as a result of erosion, but so far, no tools of man have been found in the formation.

        The development of the handaxe is not clear. It is said to be of the same antiquity, since it occurs in the deposits of the Second Interglacial period and is believed to have a development parallel to the Sohan Industry till the Third Glacial times, when a developed Handaxe Industry is met with at Chauntra (Pakistan) along with Early and Late Sohan tools).

         In Eastern Punjab, recent explorations around Kangra on the Beas and its tributaries, have also yielded evidence of industries which recall the Early Sohan and Late Sohan.