The present sediment distribution in the Arm conforms closely with the morphological features and with patterns of current flow. The original Pleistocene diamictite till deposits have been mechanically reorganized during the period following submergence of the former glaciated valley. The formation of gravel pavements in areas strongly affected by currents and fine-grained material on less current-agitated bottoms are characteristic. Intermediate sediment types, gradational between the original till and the better sorted mud and gravel end members, clearly do not fall in either relict or modern sediment categories as usually defined. The patchy nature of the sediment distribution and the wide range of textural types are characteristics common to submerged coastal embayments and shelves off glaciated regions in general.