474 STEVENSON— THE FORMATION OF COAL BEDS, [^'ov. i, 



The official reports note the not infrequent occurrence of coal 

 patches in sandstone, some of them only a yard but others several 

 rods long and wide. Without doubt, not a few of these are merely 

 blocks of vegetable matter removed by sand-laden streams during 

 change of channel-way; but others, such as that described by I. C. 

 White,"'" are unquestionably in situ. In this case, the deposit is of 

 impure cannel, 5 feet thick where opened, l)ut disappearing in all 

 directions within a few rods. It evidently marks the site of a 

 shallow pond on the sandy surface, which was filled with sapropel 

 material. It is probable that a similar explanation applies in many 

 other cases, as impure cannel is the usual material. 



Not many references to erect trees in sandstone are to be found 

 in reports on the Appalachian basin ; such trees, for the most 

 part, are rooted in shales. Lesquereux'^^'* has mentioned the occur- 

 rence of a forest of Sigillaria and Calaiiiites in sandstone over the 

 great coal bed at Carbondale in the Northern Anthracite field. This 

 seems to be the only recorded instance where the relations are 

 clear ; but Dawson^' observed several ancient soils in sandstone. 

 His Division II., 650 feet thick, has two old soils with erect trees; 

 Division III., 2,134 feet thick, has many with erect trees, the old 

 soils being in most cases very thin shale enclosed in sandstone. At 

 one locality this thin shale bears erect Calamites and shows rain 

 prints as well as footprints of batrachians ; another, somewhat lower, 

 with erect stems, has yielded several species of batrachians as well 

 as remains of insects and land mollusks ; at another, the sandstone 

 clifif shows trees as pillars of sandstone and with them are as- 

 sociated Calamites, all vertical to the bed, which is inclined at 19 

 degrees. Here the sandy flat, supporting the trees, was inundated 

 and covered with sand ; in time, the trunks rotted and were broken 

 ofif to be covered by the increasing deposit, which filled the interior 

 of the decaying stem. At another horizon, one stem rises 4 feet 

 and is surrounded by sandstone and the succeeding shale, but another 

 reaches only to the top of the sandstone. On this sandstone there 



"I. C. White, Sec. Geo!. Surv. Penn.. Rep. Q, 1878, p. 202. 



■"^ L. Lesquereux, "Geology of Pennsylvania," 1858, Vol. II., p. 840. 



■■''J. W. Dawson, "Acadian Geology," pp. 156-178. 



