Dear Mr. Wang,

to the best of my knowledge there is no quantification between the two technical terms. There exists only  a conventional subdivision between bedding and lamination at a boundary of 10 mm. Less than 10 mm you speak, e.g., of a laminated siltstone, whereas at a thickness of greater than 10 mm of a bedded siltstone.

If you want to make a distinction, call any stratification with a regionwide extension and rather small thickness a bed (also usefull in economic geology, ore bed or seam) and in case of a very limited lateral extension but relatively high vertical extension a layer. The latter is often used in ore geology.

Best regards

Harald G. Dill

Thank Mr  Dill very much for his particularly guidance and advice. I intend to semi-quantitatively study the lithological combination in my study area by the thickness and the rock type. For example, sand-mudstone-sand or mudstone-and- mudstone et al.

Harald and Ying:

Yes, there is no quantification between the two terms. Both terms suggest rhythmic sedimentation with minor to extensive lateral extent without any set limit of thickness.

Best

Syed