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lying in situ (fig. 7 — 9, phot. 5) and superglacial flowtill (fig. 7 — 7, phot. 5 — c₂). They reveal considerable enrichment with clay and coarse-grained fractions and, at the same time, impoverishment in sand fractions in relation to lodgment till, especially that of inglacial type (fig. 8). These characteristics indicate a subaąuatic environmen.t associated with retarded drainage of superglacial waters. In the Górne Sartowice section (fig. 10) subglacial till (b-) is separated from inglacial till (b₃) by ice-dammed type of deposdts about 6 m in thickness (fig. 10 — 18-9), accumlat-ed in the intraglacial water reservoir. Ice-dammed type of deposits consist of several sedimentation series sheared at the top, two of which reveal load-cast deformations (phot. 4) and fault deformations, while the remaining deposits have preserved their primary sedimentation structure. They developed as a result of recurrent drainage of the intraglacial reservoir. The most probable cause of the drainage seems to be accounted for by M. A. Rucklidge’s (1956) hypothesis, which relates the phenomenon to syphonic mechanism of water drainage in glacial channels. Inglacial till (b₃) that was melted of from the ice domed over the ice--cavern is covered with superglacial flowtill (c₂). Sharp contact between superglacial and inglacial till proves that inglacial till melted already after the forma-tion of superglacial till.

Kępa Forteczna. The summit part of this moraine plateau island is covered by the upper, youngest in the area, till strata (fig. 15). The age of the strata is testified by results of petrographic analyses (fig. 16) and till-fabric (fig. 17). Below, on the western kępa-slope are exposed deposits from the penultimate ice--sheet in the area (fig. 18). Instead of a single till strata there are superglacial sand-gravel and till deposits (fig. 18 — 4-12), which speak for the process of ice--sheet disintegration. There is also solilluction-displaced superglacial till which had been moved down on the ice slope in subaeral conditions (fig. 18 — 3). It differs in its grain-size composition (fig. 20), in fabric pattern (fig. 21) and petrographic composition from the lower lying superglacial (subaąuatic) tills. Solifluctional transportation of the till is borne out by marks of stratification (phot. 6) and the orientation and dip of long axes of pebbles which corresponds to the inclination of the stratification planes (fig. 21—a). Deposits of corresponding age on the eastern, gentle slope of Kępa Forteczna occur at a level lower by 20 m. They are represent-ed by gravelly-sandy fluvioglacial sediments cemented with calcium carbonate. They dip eastward, as the slope does (phot. 7 and 8).

Kępa of Górna Grupa. Itis composed of two main parts: of the upper, .southeastern part, whose litho-stratigraphic profile is similar to the remaining moraine plateau islands, and of the lower, north-western part comprising the area of erosive river terraces which are build of sand-and-gravel sediments insented in a large fossil groove (fig. 23).    In the    culminating    part there are fluvioglacial

deposits (phot. 17) and till (fig. 24 — I, fig. 26) from the last ice-sheet in the area, and lower rest deposits    formed    during    areał    decay    of the penultimate ice-sheet

(fig. 25 — 3-5). Just like    on the    western    slope    of the    Kępa Forteczna, superglacial-

-solifluction till is to be found here too (fig. 24 — 3, fig. 25 — 4). It fills up the hollow fossil form revealing downward thickness increase at that; the increase being characteristic for slope deposits (phot. 9). The sand-and-gravel deposits that build the river terraces    within    the Kępa of    Górna    Grupa are known from the

literaturę on the subject for the occurrence of remnants of fossil mollusks and mammals on the second bed (A. Jentzsch 1901, R. Hermann 1912, 1914, K. Kowalski 1959). The older interpretation of the time of accumulation of the remnants (R. Hermann 1914) has turned out to be incorrect because the fos-siliferous sedi-