A hundred versts above Sofyesk the scenery changed.  The mountains on the south bank receded from the river and were more broken and destitute of trees.  Wide strips of lowland covered with forest intervened between the mountains and the shore.  On the north the general character of the country remained.  I observed a mountain, wooded to the top and sloping regularly, that had a curious formation at its summit.  It was a perpendicular shaft resembling Bunker Hill Monument, and rising from the highest point of the mountain; it appeared of perfect symmetry, and seemed more like a work of art than of nature.  On the same mountain, half way down its side, was a mass of rock with towers and buttresses that likened it to a cathedral.  These formations were specially curious, as there were no more of the kind in the vicinity.  Borasdine observed the rocks soon after I discovered them, and at first thought they were ancient monuments.

There were many birds along the shore.  Very often we dispersed flocks of ducks and sent them flying over islands and forests to places of safety.  Snipe were numerous, and so were several kinds of wading and swimming birds.  Very often we saw high in air the wild geese of Siberia flying to the southward in those triangular squadrons that they form everywhere over the world.  These birds winter in the south of China, Siam, and India, while they pass the summer north of the range of the Yablonoi mountains.

The birds of the Amoor belong generally to the species found in the same latitudes of Europe and America, but there are some birds of passage that are natives of Southern Asia, Japan, the Philippine Islands, and even South Africa and Australia.  Seven-tenths of the birds of the Amoor are found in Europe, two-tenths in Siberia, and one-tenth in regions further south.  Some birds belong more properly to America, such as the Canada woodcock and the water ouzel; and there are several birds common to the east and west coasts of the Pacific.  The naturalists who came here at the Russian occupation found two Australian birds on the Amoor, two from tropical and sub-tropical Africa, and one from Southern Asia.

The number of stationary birds is not great, in consequence of the excessive cold in winter.  Mr. Maack enumerates thirty-nine species that dwell here the entire year.  They include eagles, hawks, jays, magpies, crows, grouse, owls, woodpeckers, and some others.  The birds of passage generally arrive at the end of April or during May, and leave in September or October.

It is a curious fact that they come later to Nicolayevsk than to the town of Yakutsk, nine degrees further north.  This is due to differences of climate and the configuration of the country.  The lower Amoor is remarkable for its large quantities of snow, and at Nicolayevsk it remains on the ground till the end of May.  South of the lower Amoor are the Shanalin mountains, which arrest the progress of birds.  On the upper Amoor and in Trans-Baikal very little snow falls, and there are no mountains of great height.