246 



formed of its occurrence in Emanuel, Irwin, Ware, and Colquitt. 

 I am still of the opinion, however, that the aggregate area of all 

 these outcrops will not exceed one square mile or one hundredth 

 of one per cent, of the area of the typical Altamaha,Grit region, as 

 I estimated last year. * 

 College Point, N. Y. 



LEAF-RAFTS AND FOSSIL LEAVES 



By Edward W. BhKRY 



In these modern days, with the dredging of our rivers and 

 estuaries, the draining of our marshes and the ever-widening 

 dumps of refuse that haunt the outskirts of our growing cities, it 

 would seem almost as if the old-time methods by which the vege- 

 tation of bygone geological ages was preserved had become a 

 thing of the past, and that the localities where the leaves of the 

 present flora would stand a chance of preservation and fossiliza- 

 tion had been usurped by the ever-spreading " white man's bur- 

 den." Nevertheless, in many a more remote region, leaves, fruits 

 and seeds are being stored away with a prodigality rivaling that 

 of the Mid-Cretaceous or of the European Oligocene. 



We are doubtless familiar with accounts of the vast rafts of vege- 

 tation which the Amazon and other tropical rivers bring down to 

 the sea ; however, these are largely driftwood like the famous 

 Atchafalaya raft in the Mississippi, which by rough computation 

 contained 295 million cubic feet of material and required the in- 

 tervention of the state for its removal. Similar instances in more 

 temperate climes are rarer, at least so runs the record, and I do 

 not recall any published observations on the leaf-rafts which may 

 be seen on the rivers of our southern coastal plain. These rafts 

 are sometimes of comparatively large size, especially during 

 spring freshets, at which time it is not uncommon to see them 

 from ten to fifteen feet in diameter. 



The rivers where they have been observed by the writer are the 



* See Torreya 5 : 114. 1905 ; Science II. 21 : 920. 1905 ; 23 : 486. 1906. 



