84 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



the stumps are surrounded by similar clay but the middle portion is 

 enveloped in yellow silt. A reddish loam is the superincumbent 

 material to the surface. At about a mile below the Port Hudson 

 locality, a deposit was seen, 30 feet above the stump horizon and 

 resembling a river sandbar both in structure and contents. There, 

 one finds no stumps but abundance of large drifted stems belonging 

 to several species and some of them erect. These last, as Hilgard 

 describes them, can be no other than " snags," which are even now 

 only too numerous on sandbars along the river's present channel. At 

 many places one finds living cypress swamps on the newer deposits. 



The deep oil wells of the delta, according to Harris, ^^'^ have 

 proved that there are many muck beds in the Recent deposits of the 

 delta region. 



A section measured by Colenso"* in the tin-producing area of 

 Cornwall shows features not unlike those observed by Hilgard near 

 Port Hudson: the succession is (i) Bed of river sand and gravel, 20 

 feet; (2) sand, containing tree trunks lying in all directions and 

 mostly oaks, with bones of various mammals, red deer and whales, 

 20 feet; (3) silt or clay, 2 feet; (4) sand with marine shells, con- 

 tains salt, 4 inches ; (5) sludge or silt, contains recent shells and bones 

 of mammals, 10 feet; (6) dark silt mixed with decomposed organic 

 matter, about 12 inches, on which is a layer of leaves, hazel nuts, 

 sticks and moss, 6 to 12 inches, this mass is apparently in place of 

 growth and extends with some interruptions across the valley; (7) 

 tinground, thickness varying according to irregularities of the under- 

 lying rock surface. Roots of trees are seen in this " ground " and 

 on top of it oyster shells still remain fastened to some of the larger 

 stones and to stumps of trees. The roots of oaks are in their normal 

 position and can be traced to their smallest fibers, even as deep as 

 2 feet. 



Here one has the soil of vegetation with its trees while, above it, 

 are layers containing drifted logs and others of distinctly marine 

 origin. It is worth noting that, at Sandycock in the same district, 



113 G. D. Harris, Geol. Surv. of Louisiana, Rep. for 1905, pp. 233, 240. 

 ii'ij. W. Colenso, "Description of Happy-Union Tin Stream-work at 

 Pentuan," Trans. R. Gcol. Soc. Cornzvall, Vol. IV., 1832, pp. 29-39. 



