Beds comprising white rhyolitic aphyric pumice, with particle size from ash to boulder, apparent maximum thickness of 160 meters. Clasts are angular and mutually supported, leaving bare the interim space.

Sedimentary structures (discontinuity of sub-parallel strata, lenses of semi-rounded pumice, pillow-formed shapes) and the effects of abrupt cooling of pumice fragments will support the sedimentation of the formations from precipitation of low – explosive column volcanic tephra in a shallow marine environment.

In addition to white pumice (containing few micro-phenocrysts of plagioclase and magmatic eroded quartz), gray – colored pumice with several micro-phenocrysts of plagioclase, clinopyroxene, orthopyroxene, hornblende and magnetite are observed at low percentages (3-5%).

The low percentage of lithic fragments in the deposited bed, contains cobbles of obsidian, schist substrate and rounded pumice of the Upper Ignimbrite of Kos.

An attempt to assess their age by measuring the dehydrated shell of obsidian fragments, results in a calculated age of around 50,000 years, in line with the overall stratigraphic position of the formation