[Show thumbnails] Did you know that hidden in the hills of Northwest London, you can find some of the most mysterious and scientifically significant pebbles? Unlike the sharp, broken-down gravel found elsewhere, the Stanmore Gravel Formation consists of smooth, rounded pebbles that date back 2 million years—a remnant of the Ice Age! Join us on Thursday, 17th April 2025, for Rockwatch Pebble Day at Harrow Weald Common, where you’ll follow a special pebble trail to explore these unique formations with expert geologists from the Harrow & Hillingdon Geological Society and the London Geodiversity...