CHAP. XXX.] BLUFFS OF PORT HUDSON. 139 



buried forest is covered by a bed of clay, twelve feet thick, and 

 is followed by another superimposed bed of vegetable matter, four 

 feet thick, containing logs arid branches, half turned into lignite, 

 and erect stumps, among which there are none of the large cy 

 presses, as in the lower bed. Among the logs, the water-oak 

 (Quercus aquatica) was recognizable, and a pine with a great 

 deal of bark, and the strobiles of the Pinus tceda. 



&quot; This upper forest points to the former existence, on the spot, 

 of one of those swamps, occurring at higher levels, in which the 

 Ciqiressus disticha ( Taxodium) does not grow. Above the 

 upper layer of erect stumps are various beds of clay, in all more 

 than fifty feet thick, with two thin layers of vegetable matter 

 intercalated ; and above the whole more than twenty feet of sand, 

 the lower part of which included siliceous pebbles derived from 

 some ancient rocks, and containing the marks of encrinites and 

 corals (Favosites),&quot; &c. 



Dr. Carpenter, when he published this account in 1838, 

 thought he had detected the distinct marks of the ax* on some 

 of the logs accompanying the buried stumps ; but he informed 

 me, in 1846, that he was mistaken, and that the apparent 

 notches were caused by the gaping open of the bituminized wood, 

 probably after shrinking and drying, of the truth of which I was 

 myself convinced, after seeing the specimens. That the lowest 

 bed had originally been a real cypress swamp, was proved beyond 

 all doubt by the stumps being surrounded by those peculiar knobs 

 or excrescences called cypress knees, which this tree throws out 

 from its base, when it grows in a submerged soil. These knees 

 sometimes rise up through the water from a depth of six or eight 

 feet, and are supposed to supply the roots with air, as they are 

 never formed when the cypress grows on dry ground. 



At the time of my visit, the river was unfortunately too high 

 to enable me to see the lowest deposit containing the memorials 

 of this ancient forest, the geological interest of which is much 

 enhanced by its having been seen by Bartram, and again by 

 Carpenter, extending horizontally over a considerable area. I 

 learnt from several residents at Port Hudson, and from Captain 

 * Silliman. ibid. p. 119, 



