In the Eden Valley at the foot of the North Pennine escarpment lie red sandstones which give the villages along the foot of the fells their distinctive character.

Dunes and flash floods

The red sandstones formed between 290 and 210 million years ago, in the Permian and Triassic periods of Earth history. Northern England lay just north of the equator in similar latitudes to the present-day Sahara. In the Permian Period, the North Pennines was a hot and arid place with rocky hills, sand dunes and salt flats. In Triassic times, flash floods and seasonal rivers spread across the desert plains.

Sand to sandstone

The sands from the deserts and rivers hardened into the red sandstones of the Eden Valley, to the west of the North Pennine escarpment. The two main sandstones are the Penrith Sandstone and the younger St Bees Sandstone. These rocks are most evident in the warm red building stones of the towns and villages along the foot of the escarpment.

Clues to the past

Evidence of these ancient desert environments is preserved in the rocks. The sand grains in the Penrith Sandstone are spherical, their shape formed by relentless wind blasting. The slopes of large dunes are also preserved in the sandstone and indicate that the wind in this ancient desert blew from the east-south-east.