Cherry Hinton Chalk Pit
Just inside the present city boundary lies an abandoned chalk quarry. Material from the quarry was used to build the colleges and other buildings in Cambridge and also to make lime for agricultural use. Nothing has been extracted from these works since the 1980s and the quarry is being allowed to return to a more natural state.
The site gives botanists an opportunity to study how plants colonise what was originally bare chalk. As you can see there's already quite a floral show, though with a fairly limited range of species. Most of the yellow in the scene above is Bird's-Foot Trefoil, or Eggs-and-Bacon as it's sometimes known from the colour of its flowers. It's a naturally occurring plant in England whereas elsewhere it can be a troublesome invasive species. But there are other yellow flowers here too.....
Above is Yellow-Wort, a plant often found on chalky soils.
The chalk itself was laid down when this area was underwater, about 100 million years ago. It consists mainly of the microscopic remains of algae and unsurprisingly it took a long while to accumulate - about 1cm every 1,000 years, it's been calculated! Chalk is usually white, but here it contains layers that are tinted yellow or pink by impurities too. You can just about make out these in the photo above.
Various Dandelion-like Hawkweeds are also colonising this unpromising environment. And those cliffs around the quarry edge are home to nesting Peregrine Falcons. They are also sometimes spotted on the University's buildings in the centre of Cambridge as they await their lunch, a nice fat pigeon perhaps, to flutter into view.
One part of the reserve has not seen any quarrying activity for a couple of centuries and has, over the years, developed into an area of woodland. It was here that I came across a stand of St John's Wort (below).
Then it was time to pedal on to....
Nothing could be more different from the recovering landscape of the chalk-pits than the unimproved meadowland of Fulbourn Fen. Although I couldn't resist calling the post "Chalk And Cheese" I don't really know if cheese was produced from the milk of the animals that have grazed this area for centuries, but it seems likely.
These traditionally managed hay meadows have retained their original glory, having never been ploughed or "improved" by the application of chemical fertilizers or pesticides. Although they are still privately owned, they are managed with the help of the Wildlife Trust and the public are allowed to roam around on the network of paths and enjoy the scenery.
Wildflowers grow here in abundance and there are plenty of bees and butterflies taking advantage of the nectar supply.
In summer the fields are reasonably dry with just a few small ponds to supply water for livestock.
In one of the wetter parts Wild Iris or Flags were blooming, but these are not the flowers that attract the human visitors...
Orchids, particularly the Southern Marsh Orchid, grow in hundreds in one of the meadows. And there are smaller numbers of at least five other species of orchid.
There are still several large trees spreading their shade for the benefit of the cattle that graze here in the heat of summer. On Sunday there were a couple of families picnicking here - young naturalists in the making perhaps. And there by the fence was my faithful "horse" waiting to take me home.