Svirkanai outcrop is located on the left bank of Virvytė, Svirkanai recreation area, Svirkanai village, Viekšniai eldership. Its height is about 14.5 m and its length is about 50 m.
The Svirkava outcrop is an object of geological heritage of high scientific value. The section of the outcrop consists of two complexes of structures of different origins and ages. The lower part (7.7 m upwards from the river water level) is made of siltstone and fine sand. This is the sediment of the lake that existed before the last ice age, about thirty thousand years ago (during the Middle Nemunas period). According to palinological studies, the lake existed in relatively cold climates, surrounded by tundra with shrubs and rare trees, but at that time the continental glacier was still quite far to the north, probably to the south of Finland. The Paleo Lake of the Middle Nemunas was large, with an area of about 77 square meters. km. For comparison - Lake Dusia occupies 23 sq. Km. km, and the largest (partly) Lake Druksiai in Lithuania - 100 square kilometers.
There are only a few lake sediment outcrops of the Middle Nemunas period in the whole Baltic region (Roka outcrop in south-eastern Lithuania, Voka in Estonia). One of the most recently explored outcrops is the Mire Outcrop in the Venta Valley.
The upper part of the exposure section is made of moraine material left by the continental glacier, which covered almost the whole of Lithuania with its shield during the last ice age. It is interesting to note that the layer of moraine material is bilayer, consisting of a very hard bottom moraine and a massively textured ablation (glacier melting phase) moraine. Both moraine is separated by a 0.8–1.0 m thick layer of fine sand formed in the internal cracks and cavities of the glacier.