In the course of the day we met with very open and rotten ice, which would only have been of use to us by its moderating effect on the sea, if it had not been accompanied by the usual attendant of the border of the ice, a thick fog, which however sometimes lightened. Towards evening we came in sight of Beli Ostrov. This island, as seen from the sea, forms a quite level plain, which rises little above the surface of the water. The sea off the island is of an even depth, but so shallow, that at a distance of twenty to thirty kilometres from the shore there is only from seven to nine metres of water. According to a communication from Captain Schwanenberg, there is, however, a depth of three to four metres close to the north shore. Such a state of things, that is, a uniform depth, amounting near the shore to from four to ten metres, but afterwards increasing only gradually and remaining unchanged over very extensive areas, is very common in the Arctic regions, and is caused by the ice-mud-work which goes on there nearly all the year round. Another remarkable effect of the action of the ice is that all the blocks of stone to be found in the sea next the beach are forced up on land. The beach itself is formed accordingly at many places, for instance at several points in Matotschkin Sound, of a nearly continuous stone rampart going to the sea level, while in front of it there is a quite even sea bottom without a fragment of stone. [Illustration: SECTION FROM THE SOUTH COAST OF MATOTSCHKIN SOUND. Showing the origin of Stone-ramparts at the beach. ] _August 4th._ In the morning a gentle heaving indicated that the sea was again free of ice, at least over a considerable space to windward. Yesterday the salinity in the water was already diminished and the amount of clay increased; now the water after being filtered is almost drinkable. It has assumed a yellowish-grey colour and is nearly opaque, so that the vessel appears to sail in clay mud. We are evidently in the area of the Ob-Yenisej current. The ice we sailed through yesterday probably came from the Gulf of Obi, Yenisej or Pjaesina. Its surface was dirty, not clean and white like the surface of glacier-ice or the sea-ice that has never come in contact with land or with muddy river-water. Off the large rivers the ice, when the snow has melted, is generally covered with a yellow layer of clay. This clay evidently consists of mud, which has been washed down by the river-water and been afterwards thrown up by the swell on the snow-covered ice. The layer of snow acts as a filter and separates the mud from the water. The former, therefore, after the melting of the snow may form upon true sea-ice a layer of dirt, containing a large number of minute organisms which live only in fresh water.