Dr. Ritesh Arya Visits Gilbert Hill: A Forgotten Geological Treasure in Mumbai's Urban Jungle

PRESS NOTE Dr. Ritesh Arya Visits Gilbert Hill: A Forgotten Geological Treasure in Mumbai's Urban Jungle Mumbai, 15 June 2025 — Renowned geologist and Tethys Fossil Museum Director Dr. Ritesh Arya visited Gilbert Hill, one of Mumbai’s most extraordinary geological monuments, known for its 66-million-year-old columnar basalt formations—the remnants of the Deccan volcanic activity that possibly contributed to the extinction of dinosaurs. What should have been a celebrated natural wonder turned out to be a neglected site struggling to breathe under concrete and urban sprawl. Dr. Arya had to make considerable effort to locate Gilbert Hill, now nearly hidden amidst buildings and lacking directional signage or any display of geological significance. Though declared a National Geological Monument by the Geological Survey of India (GSI), the site's preservation tells another story. The GSI has attempted conservation by drilling, bolting, and grouting to stabilize the columnar joints, but cracks are still visible and rockfalls continue, posing potential hazards. The columnar jointing—hexagonal basalt columns that formed during the slow cooling of lava—can still be seen along the stairway leading to the top, and partly from the base, offering visitors a glimpse into Earth’s deep past. Unfortunately, the temple trust maintaining the site has constructed a temple over the top, covering the surface where the most distinct hexagonal patterns could have been appreciated. This development has obscured the core geological features that make Gilbert Hill globally significant. > “If even a small area were left exposed to reveal the stunning hexagonal columns, it would be a transformative geotourism experience—especially for children and students,” said Dr. Arya. “This site is a natural textbook, linking volcanic history with mass extinction events like that of the dinosaurs. It deserves better visibility and interpretation.” Dr. Arya emphasized the urgent need for geoscientific interpretation boards, educational signage, and proper access to the site. He will be submitting recommendations to concerned authorities and has offered his support to develop Gilbert Hill into a flagship geoheritage and geotourism destination in Mumbai. Interestingly, Dr. Arya recently discovered a 20-million-year-old palm leaf fossil near Gilbert Trail in Kasauli, further connecting India’s paleontological and volcanic past. He believes that drawing such connections across Indian geoheritage sites can inspire a new generation of geoscientists and nature lovers