Perhaps the soil is too clayey or insufficiently drained.
The clayey earth was as cracked as the face of an old oil painting.
Thickness of individual silt beds increases towards the top, while representation of clayey silt layers decreases.
The fault planes are characterized by anastomosing clayey gouge layers with thin (1 mm-10 cm) zones of cataclasite, breccia and hematite-clay-coated fractured rock.
All but one of the stands sampled were on clayey soils.
The matrix of the specimens is a light-grey clayey limestone.
The significant positive effect of soil clay content on the clustering of trees could be due to the higher water retention capacity of clayey soils.