at the shore of Polavina Point, St. Paul, show in a striking manner a section of the geological structure of the island. The tufas on both islands, at the surface, decompose and weather into the base of good soil, which the severe climate, however, renders useless to good husbandmen. There is not a trace of granitic or of gneissoid rocks found _in situ_. Metamorphic boulders have been collected along the beaches and pushed up by heavy ice-floes which have brought them down from Siberian coasts far away to the northwest. The dark-brown tufa bluffs and the breccia walls at the east landing of St. Paul Island, known as “Black Bluffs,” rise suddenly from the sea sixty to eighty feet, with stratified horizontal lines of light-gray calcareous conglomerate, or cement, in which are embedded sundry fossils characteristic of and belonging to the Tertiary Age, such as _Cardium grœnlandicum_, _C. decoratum_, and _Astarte pectunculata_, etc. This is the only locality within the purview of the Pribylov Islands where any palæontological evidence of their age can be found. These specimens, as indicated, are exceedingly abundant; I brought down a whole series, gathered there at the east landing or “Navastock,” in a short half-hour’s search and labor. Although small quantities of drift-wood lodge at all points of the coast, yet the greatest amount is found on the south shore, and thence around to Garden Cove; this drift-timber is usually wholly stripped of its bark, principally pine and fir sticks, some of them quite large, eighteen inches or two feet in diameter. Several years occur when a large driftage will be thrown or stranded here; then long intervals of many seasons will elapse with scarcely a log or stick coming ashore. I found at Garden Cove, in June, 1873, the well-preserved husk of a cocoanut, cast up by the surf on the beach: did I not know that it was most undoubtedly thrown over by some whaler in these waters, not many hundred miles away at the farthest, I should have indulged in a pretty reverie as to its path in drifting from the South Seas to this lonely islet. I presume, however, that the timber which the sea brings for the Pribylov Islands is that borne down upon the annual floods of the Kuskokvim and Nooshagak Rivers on the mainland, and to the east-northeastward, a trifle more than two hundred and twenty-five miles; it comes, however, in very scant supply. I saw very little drift-wood on St. Matthew Island; but on the eastern shore of St. Lawrence there was an immense aggregate, which unquestionably came from the Yukon mouth.