The stratigraphic contact of two separate geological formations, particularly the upper molassic sediments of Lemnos and the pyroclastic formations of Romanos, is located north of the ancient site of Poliochni on the slopes of the scenic harbor. Clays and sandstones with interstitial cobblestones (rock with rounded pebbles within) in the lower layers, aged about 23 million years, can be found with a general dip direction to the NW under the Lower Miocene tuff.

Marine sedimentogenesis occurred between 22 and 28 million years ago, resulting in the sedimentary formations of Lemnos. Around 22 million years ago, the earliest volcanic products of Lemnos, pyroclastic rocks with layers of volcanic ash with various rock fragments, settled over these sedimentary rocks.

At this location, the movement of tectonic faults in the NE-SW direction alters the layers and brings older sedimentary formations into contact with younger volcanic formations, resulting in a complicated geological picture.