If you push your garden fork into the ground in Grovehill you can find clay or clay-with-flints, stones and pebbles, possibly a little chalk. This is how it all came to be there.
The sea covered what we think of as our land. In the passing of time sea creatures died and their shells fell to the deep bottom of the sea and became what we call chalk. Some of the shells were preserved in the chalk and can still be found locally as fossils.
MICRASTER: A fossilised sea urchin found in the chalk near Dunstable Downs
You can see the chalk where the park gives way to the fields and at Ivinghoe Beacon and Dunstable Downs. You can see this chalk layer wherever there are building works or road works.
This dell from where chalk would have been dug to improve the soil is in one of the fileds at the edge of the town. There were others were Jarvis Dell and Bugdal Dell. This is the origin of 'dell' in many local place names.
A CHALK DELL
Were there really chalk mines dating around 1700-1900 in Hemel? Yes, one of them collapsed under a house recently. They were possibly cut by Anglo Saxons.
You can find flint nodules in that formed in the chalk from silica. The odd shapes come from un-solidified silica from the shells of dead sea creatures filling in the holes left by the remains of the creatures.
You don't often find whole nodules like this one which was white when dug out of the clay, they are usually broken.