CHAP. XXX.] BLUFFS OF PORT HUDSON. 179 



jf 



Juylans nigra. The logs lying horizontally are those 

 of the cypress ( Cupressus thyoides), swamp hickory, 

 a species of cotton wood (Populus), and other trees 

 peculiar to the low swamps of Louisiana. Besides 

 these there were a great number of erect stumps of 

 the large deciduous cypress (Taxodium distichum) 

 sending their roots deep into the clay beneath. This 

 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 and 

 branches, half turned into lignite, and erect stumps, 

 among which there are none of the large cypresses, 

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

 oak ( Quercus aquatica) was recognisable, 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 Cupressus disticka ( Tax- 

 odium) 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 vege 

 table 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 axe* on some of the logs accompanying the 



* Silliman, ibid. p. 119. 

 i 6 



