Extremely sheltered gravelly mud on the mid and lower shore, containing little sand with occasional cobbles. The infaunal community includes the ragworm Hediste diversicolor and the peppery furrow shell Scrobicularia plana, as well as a range of polychaetes, oligochaetes, and molluscs. Given the low sample numbers for this biotope, more records are needed to confirm the characterising species list. Situation: It is probable that there are broad transition areas between this unit and the corresponding muddy sediment biotope A2.313. The boundaries may be very indistinct, with unit A2.4112 present in patches of gravelly mud on areas of mudflat, where the main biotope is A2.313.