In the region of the Minato City area facing onto Inner Tokyo Bay, a different type of Jomon-Period shell mound has been confirmed, from which we can learn about the various lifestyles led. The layers of shells of Isarago Shell Mound stretch over an area of around 351m2, and were deposited at 1.8m thick in places. The fact that it contains few food remains other than shells, or earthenware tools etc., and that traces of fire-lighting have been found, suggests that this place was a processing plant for shelling shells. On the other hand, Nishikubo Hachiman Shell Mound is a small-scale shell mound, and since food remains such as fishbones and animal bones, as well as numerous earthenware and stoneware have been excavated, it could be considered a rubbish tip for a dwelling site.