Barnack Hills and Holes

Hills and HolesOtherwise known as Hills and Hollows this is a National Nature Reserve and a Site of Special Scientific Interest.

Its undulating mounds are the result of limestone quarrying in medieval times. The stone that was quarried here was Lincolnshire Limestone from the Jurassic period (205-142 million years ago). Known as Barnack Rag, it is a buff-yellow limestone that has been extensively quarried in the area since Roman times and was used in the construction of many of the local village houses and most impressively for both  Peterborough and Ely Cathedrals.

The blocks of stone were transported on sleds across to the River Welland and then loaded onto barges which travelled down the river Nene and other fenland waterways to also be used for the abbeys at Crowland, Ramsey, Sawtry and Bury St. Edmunds.

The site covers 50 acres, made up of rare limestone grassland which is home to several species of orchids, purple milk-vetch, common rock-rose and an abundance of pasque flower. This rich flora supports a wide variety of  insects  and a number of species which are nationally scarce can be found in Hills and Holes including marbled white, chalkhill blue, brown argus and green hairstreak butterflies.

 CowslipsHills and Holes is open all the year round and parking is available at several points on the edge of the reserve, although the main visitor car park is on Wittering Road.

The best time to see the flora is in June and July, when many areas are swathed in blue, white pink or yellow flowers. Many of the tiny orchids can be found at this time along with other lime-loving plants such as quaking grass, rockrose, wild thyme, violets, cowslip and ox-eye daisy.

Later in the year other species such as carline thistle, clustered bellflower  and autumn gentian may be seen.

The Limestone grassland of the Hills and Holes  is managed by grazing with up to 300 sheep in autumn. Without grazing, the build-up of coarse grasses would soon choke out the rarer lime-loving plants. Shrubs and bushes,  if left unchecked, would rapidly take over the site and these are cleared regularly from the open grassland but a few areas are left as a habitat for birds and other wildlife.

There is a circular 30-minute walk known as the Limestone Walk which takes you through all the main features of the reserve. Simply follow the orange arrows from the main car park.