The largest glacier of the Petuniabukta area is the Hörbyebreen. It is among the tew on Spitsbergen whose marginal zones undergo areal decay. What has made in this type of glacier is a rich supra-glacial moraine cover that was formed as a result of a deformation of debris bands in the frontal part following a surge. In the marginal zone three subzones were distinguished differing in the degree of degradation of passive ice that covers almost all its area. They also differ in the stability of deposits and in the relief.

At the outlet of the Hörbyedalen, at the footslope of Gizehfjellet, lies a fragment of a raised marine terrace of an altitude of 45 m above sea-level. It is undercut by a proglacial river constituting an exposure with a series of marine, fluvio-glacial and moraine deposits. A lithological characterisation of the deposits was carried out, and radiocarbon dating and TL analysis were used in an attempt to present the chronostratigraphy and development of glacial and marine events in the Hörbyebreen during the Vistulian and the Holocene.

During geomorphologic mapping of northern seashore of Hornsund (Spitsbergen) a geomorphologic map of Revdalen and Fuglebergsletta was prepared in the scale of 1: 10 000. Distinct outwash routes and a moutonnee area was noted to the south of Rewatnet; at the same time, the destroyed marine terraces in the upper part of the valley and an occurrence of a ground moraine there, prove a Holocene glacier advance in Revdalen (about 2 400 years B. P.). The glaciers of that time slightly overcrossed a zone of the present southern limit of the Rev Lake but they did not fill entirely the middle part of the Revdalen.

During the expedition "Spitsbergen 1979/80" the authors prepared a geomorphologic map of the area to the north of Hornsund, between the Torell Glacier and the Treskelen Peninsula. Fifteen raised marine terraces were distinguished. Basing on field morphometric sections, quite a detailed distribution of the terraces at a seaside plain and in side valleys was noted. Also, the previous Polish studies over this part of the Svalbard Archipelago were taken into account. The terraces occur at the following altitudes: 220—230 m, 200—205 m, 180—190 m, 100—115 m, 80—95 m, 70—75 m, 60—65 m. 45—46 m, 40 - 46 m, 32—35 m, 22—25 m, 16—18 m, 8—12 m, 4.5—6 m and 2 m a.s.l. (Figs. 2—5). The terraces are not evenly distributed and they possess a varying structure. The authors, due to absence of other chronologic evidence but on the ground of a morphologic analysis and radiocarbon data (presented by Birkenmajer and Olsson 1970) suppose that only the lowest terraces have been formed in a postglacial period.

The analyzed ridges posses a varying morphology and dimensions. They are composed of rocky blocks of local origin only. The blocks are chaoticly arranged although a position transversal to a morphologic axis of the ridge predominates. The ridges occur mainly in places where distinct structural loosenings of the mountain massifs are noted, at the foot of fresh slopes. They define the periods when rockfalls were most intensive. The authors found the subslope ridges to be the nival moraines.