New Delhi, July 2 -- Presumed ancient carvings on quartzite rocks in Delhi's Central Ridge, near the Delhi Polo Club, have been discovered by environmentalists, marking the first likely record of a petroglyph in the Central Ridge, experts said. Similar rock carvings have previously been documented around the Jawaharlal Nehru University (JNU) campus, while prehistoric stone tools have been found near the Kamla Nehru Ridge. Experts said neighbouring Bhondsi, Surajkund, Mohabatabad, Dhauj, Kot and Alwar have also yielded similar engravings and stone tools. Environmentalist Pradip Krishen, who made the discovery with environmentalist Chetan Agarwal, said he noticed the carvings during a walk last week. "We (Chetan and I) happened to notice this large rock which was not too far from the polo grounds. Although I've walked this path many times, the rock is easy to miss. We so happened to notice it this time around," he said, adding that researchers believe the carvings appear significantly old. Agarwal said the find is likely the first record of petroglyphs in the Central Ridge. Previously, they have been found in JNU and around the northern Ridge. We have also seen ample evidence on the Haryana side, around Anangpur, Mangar and Bhondsi, including caves where such carvings exist," he said, adding that a detailed study would provide greater clarity. HT showed photographs of the carvings to a historian specialising in rock engravings, who confirmed they appeared to be petroglyphs but did not wish to be quoted. Experts also confirmed the images, accessed by HT, appeared to include cupule art. Archaeologist Banani Bhattacharyya, former deputy director of the department of archaeology in Haryana, said the linear petroglyph engraved on quartzite comprises intersecting vertical and horizontal grooves forming a ladder-like geometric design and is likely thousands of years old, though scientific dating is required. She said similar engravings documented at Mangar suggest possible prehistoric cultural continuity and stressed the need for systematic documentation, archaeological investigation and scientific dating to establish their chronology and cultural context....