554 STEVENSON— FORMATION OF COAL BEDS. [November 3, 



as containing the statement that Professor Smith had seen a floating 

 mass about 120 feet long and probably washed out of the Congo, 

 consisting of reeds resembling Doiia.v and a species of Agrostis, 

 among which branches of a Justicia were still growing. Powers*^ 

 saw a floating island in the Gulf Stream in July of 1892. Its area 

 was estimated at about 9,000 square feet and it carried trees, 30 

 feet high. It was seen again in September, having travelled more 

 than 1,000 nautical miles. This, first seen in latitude 39° 5', may 

 have been torn off from the Florida coast. In every case the float- 

 ing islands are of small extent and their rarity makes them objects 

 of curious interest. 



Drifhvood. — Great rivers carry immense quantities of trees from 

 the undermined banks. Where the course of the stream is inter- 

 rupted by extensive lakes, such as Great Slave or Athabasca, much 

 of the floating timber becomes scattered and is cast on the shore to 

 Tdc mingled with the mineral material, which eventually buries it. 

 When the stream is continuous, some of the drift is cast ashore 

 in eddies, more is stranded during flood time on the delta or in shal- 

 lows at the mouth ; but by far the greater part is swept out to sea, 

 there to be battered by the waves or carried by currents to perhaps 

 •distant shores. NordenskiokP- relates that driftwood in the form 

 of small branches, pieces of roots and whole trees with adhering 

 portions of roots and branches, occurs in such quantity at the bottom 

 of two well-protected coves near Port Dickson, that the seafarer 

 may provide a sufficient stock of fuel without difticult}'. The great 

 mass of driftwood carried down by the Yenesei floats out to sea. 

 Some of it is drifted by currents to Nova Zembla, the north coast of 

 Asia, Spitzbergen, perhaps to Greenland. Some of it becomes water- 

 soaked and sinks before reaching those shores. But not all goes to 

 sea, for some sinks in the river bed, upright as though rooted in the 

 sands. A bay off Port Dickson was found barred by a palisade of 

 driftwood. 



"S. Powers, "Floating Islands," Pop. Sci. Monthly, Vol. LXXIX., igir, 



PP- 30.3-307. 



'■^A. E. Nordenskiold, "The Voyage of the Vega around Asia and 

 Europe," New York, 1882, pp. 152-154. 



152 



