66 THE PRESERVATION OF PLANTS AS FOSSILS. [CH. 



wood were seen at right angles to the direction of the river; 

 uprooted trees, logs, branches, and bark, often floating separately. 



" The midribs of the leaves of a pinnate-leaved palm were abmidant, 

 and also the stems of a large cane grass (Saccharum), like that so 

 abundant on the shores of the great river in Fiji. Various fruits of trees 

 and other fragments were abundant, usually floating confined in the midst 

 of the small aggregations into which the floating timber was everywhere 



gathered Leaves were absent except those of the Palm, on the midrib 



of which some of the pinnae were still present. The leaves evidently 

 drop first to the bottom, whilst vegetable drift is floating from a shore ; 

 thus, as the debris sinks in the sea water, a deposit abounding in 

 leaves, but with few fruits and little or no wood, will be formed near 

 shore, whilst the wood and fruits will sink to the bottom farther off the 

 land. Much of the wood was floating suspended vertically in the water, 

 and most curiously, logs and short branch pieces thus floating often 

 occurred in separate groups apart from the horizontally floating timber. 

 The sunken ends of the wood were not weighted by any attached masses 

 of soil or other load of any kind ; possibly the water penetrates certain 

 kinds of wood more easily in one direction with regard to its growth than 



the other, hence one end becomes water-logged before the other The 



wood which had been longest in the water was bored by a Pholas^." 



The bearing of this account on the manner of preservation 

 of fossils, and the differential sorting so frequently seen in plant 

 beds, is sufficiently obvious. 



As another instance of the great distance to which land 

 plants may be carried out to sea and finally buried in marine 

 strata, an observation by Bates may be cited. When 400 miles 

 from the mouth of the main Amazons, he writes : 



"We passed numerous patches of floating grass mingled with tree 

 trunks and withered foliage. Amongst these masses I espied many fruits 

 of that peculiar Amazonian tree the Ubussii Palm ; this was the last I 

 saw of the great river^." 



The following additional extract from the narrative of the 

 Cruise of H.M.S. Challenger illustrates in a striking degree the 

 conflicting evidence which the contents of fossiliferous beds 

 may occasionally afford ; it describes what was observed in an 

 excursion from Sydney to Browera Creek, a branch of the main 

 estuary or inlet into which flows the Hawkesbury river. It 



1 Challenger (85), Narrative, vol. i. Pt. ii. p. 679. 

 ' Bates (63) p. 389. 



