We have been concentrating on the feature previously known as Idris’s Doughnut and trying to find ‘the natural’. The Doughnut continues to grow and now seems to be a made cobble platform of some sort & probably pre-dating the existing buildings in the area. The surface a short distance below it certainly pre-dates them – it was probably there when humans returned to the area as the ice retreated at the end of the last ice-age (not the film fyi). In different parts of the trench, Steven & Catherine dug through this grey silt and clay strata to expose a layer of stones dropped by the glacier as it traveled through the valley. These layers are ‘the natural’ so mission partially accomplished. In another sondage, in another part of the trench, Gayle had started to expose the top of what looks like the the silty layer by the end of the day.
Steven’s journey into the deep past involved the pictured sondage within a sondage. The stoney layer is so closely packed that we were unable to get the point of the ranging rod into the ground. The white section (NOT including the point) is 50cm which gives some idea of the thickness of this layer. The silt and clay was probably deposited when the area was covered by a lake or slow moving body of water.
Find Of The Day comes from the layer of stones below the silt. It’s a decent sized lump of sandstone that the glacier has carried from where it was formed and then dropped in our trench. There it sat patiently for about 15000 years or more, waiting for Catherine to come along and wrest it from it’s resting place. These bits of stone that drop from the bottom of the glacier are known as glacial erratics.
The Beast Of The Day has two rather splendid names – Pseudargyrotoza conwagana for formal occasions but Yellow Spot Twist to its friends.
Tomorrow we are hoping to unearth some more clues about our pebble made feature.