STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 83 



a succession of peat beds, separated by clay, sand or marl, while 

 peat is forming on the present surface. Some of these beds show 

 trees rooted in the underlying material. 



Soils of l^egetation. — The rocks intervening between peat hori- 

 zons occasionally show what may be termed soils of vegetation, on 

 which plants grew but no peat accumulated. Thomson"^ states that 

 in making excavation for a naval dock in Bermuda, this succession 

 was found, beginning at 25 feet below the surface : ( i ) Calcareous 

 mud, 5 feet; (2) coral crust, 20 feet; (3) a kind of peat and vege- 

 table soil, containing stumps of cedars in vertical position and the 

 remnants of other land vegetation with remains of Helix hermndi- 

 cnsis and of several birds. 



This old soil of vegetation rests on the usual ''base rock" of 

 the islands. Buried soils of vegetation have been noticed by all 

 students who have visited the Bermudas. They are distinct at several 

 places along the south shore where, in 1895, the dead cedar forest 

 with trunks still erect protruded through the seolian beds, which 

 in many spots were already covered with a dense growth of oleander 

 and young cedars. No peat is found in the Bermudas except in 

 " sinkholes " and estuaries ; the porous rock permits rainwater to pass 

 down quickly to tide level so that neither spring nor stream exists 

 on the islands ; but one finds buried soils with Helix and plant 

 remains at various levels in the " sandstone " as the slightly consoli- 

 dated ffiolian rock is termed. 



Hilgard^^- saw, near Port Hudson on the Mississippi, brown muck 

 overlying white or blue clay and underlying 93 feet of later deposits. 

 This muck, 3 to 4 feet thick, contains cypress stumps, representing 

 three, perhaps four generations. The stumps are rooted in the tough, 

 somewhat sandy underclay. A similar deposit was seen at many 

 places within lower Louisiana and usually several generations of 

 cypress trees are shown. At one locality, huge stumps, 5 to 8 feet 

 high, have their roots buried in a stratum of brown clay ; the tops of 



111 C. W. Thomson, " The Atlantic," 1878, Vol. I., pp. 297, 298. 



112 E. W. Hilgard, " On the Geology of Lower Louisiana and the Salt 

 Deposit on Petite Anse Island," Siiiithson. Contrib., No. 248, 1872, pp. 5, 6, 

 7, 9, II, 26. 



