i6o 



THE CHAIN OF LIFE. 



swamp was exposed to the invasion of muddy and sandy 

 sediment, and this went on accumulating until the stem of the 

 tree was buried to the height of about nine feet, before v.^Mch 

 time it was no doubt killed. After a time the top decayed and 

 fell, leaving the buried stump imbedded in the sandy soil, 

 which had row become dry, or nearly so. The trunk decayed, 

 its inner bark and axis rotting away and falling in shreds into 

 the bottom of the cylindrical hole, about nine feet deep, once 

 occupied by the stem, and now kept open like a shaft or well 

 by the hard resisting outer bark. The ground around this 

 opening became clothed with ferns and reed-like Calamitcs, 

 partly masking and concealing it. And now millepedes and land 



J'lG. 140. — Stction showing the position of r\n erect Sigillaria, conUiining remains ox 



land aniniuls. 



1. Undcrclay, with rootlets of Stigmaria, resting on gray shale, with two thin coaly 



seams. 

 5. (iray sandstone, wiih eicv,: trees, Calamitcs, and other stems : 9 feet. 

 ■),. Coal, with erect tree on its surface: G inches. 

 n. Underclay with Stigmaria rootlets. 



a, Calamites. c, Stigmaria roots. 



i). Stem of plant undetermined. a', Krect truik, 9 feet high. 



snails made the buried trunk a home, or fell into it in their 

 wanderings; and small reptiles sporting around, in pi'isuit of 

 prey, or themselves pursued, stumbled into the open pitfall, 

 and were unable to extricate themselves, though I have found 

 in some of the layers in these trees trails which show that these 



