I9I2.] STEVENSON— THE FORMATION OF COAL BEDS. 491 



become submerged quietly. LyelP* visited this locality at a later 

 date when a quarry had been opened in the overlying sandstone. 

 He saw the trees in a clay shale underlying sandstone and i8 feet 

 above a coal bed. He, with Owen, dug the clay from about one of 

 the trees, which was 4 feet 8 inches high and with roots spreading 

 out as in the normal position. This and two other SigiUaria, close 

 by, were casts, the bark converted into coal but the interior filled 

 with mud. The roots were interlaced. A great number of such 

 trees had been removed in working the quarry. Udden'^ notes 

 that a vertical stump resting on a coal bed was seen by him near 

 Peoria, Illinois, but he gives no details aside from the statement 

 that the stump is filled with sandy clay. 



There is, however, no lack of information respecting other lands. 

 Dawson and R. Brown have recorded many instances in the Acadian 

 region ; in one case there are Sigillaria stumps with Stigmaria root- 

 lets descending among them from an overlying bed. Occasionally 

 an embryo coal bed existed in the old soil but in some cases there 

 is no trace of coal. The absence of vegetable matter around the 

 base of the stems is in no sense evidence that they are not in place, 

 for Tuomey, as cited on an earlier page, has shown that peat beds 

 raised above the level of water-supply, waste away by drying, the 

 removal being aided by the winds, which carry off the dust-like 

 material. The trees remain, rooted in the underlying soil. Many 

 other students of peat deposits have made the same observation in 

 later years. Gruner says that the lower forest of Treuil has the 

 roots spread out in the roof of the coal and that it is present except 

 where the roof has been washed away and replaced with sandstone. 

 Hawkshaw'^ described the trees found at Dixon Fold near Man- 

 chester. Five of them, at nearly right angles to the stratification, 

 were embedded in a soft blue clay, and a thin coal bed on same 



'*C. Lyell, "A Second Visit to the United States of North America," 

 2d ed., 1850, Vol. II., pp. 272, 273. 



"J. A. Udden, "Geology and Mineral Resources of the Peoria Quad- 

 rangle," U. S. Geol. Surv., Bull. No. 506, 1912, p. 37. 



'*J. Hawkshaw, "Descriptions of the Fossil Trees found in the Exca- 

 vations for the Manchester and Bolton Railway," Trans. Geol. Soc, II., Vol. 



VI., 1842, pp. 173-175. 



