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



tinned its work of destruction until weakened by spreading over the 

 great plain of the Rhone valley. After ravaging Le Bourg and the 

 village of Martigny, it fell with comparative tranquillity into the 

 Rhone, " leaving behind it on the plain of Martigny the wreck of 

 houses and furniture, thousands of trees torn up by the roots and 

 the bodies of men and animals, which it had swept away." 



Neither landslide nor vast flood can be invoked for explanation 

 of phenomena such as those described by Adamson, Potonie and 

 Binney. It is incredible that the work of such destructive agents 

 would leave no record except a group of trees resting normally with 

 the roots of one interlaced with the roots of the others. There is 

 no trace of disturbance at any locality mentioned by the observers 

 named or by any others; yet the discoveries by Binney, Hawkshaw, 

 Bowman and Piatt are in the same small area, each covers a con- 

 siderable space and everywhere there is evidence of wholly undis- 

 turbed deposition. The evidence that the trees are in situ is as 

 strong as it is for Russell's gravel buried forest in Alaska or for 

 the sea-covered forests on the shores of the Baltic and Britain. 



The trees in situ, the ripple marks, rain and footprints, the evi- 

 dence of selective action by streams, all go to show that shales were 

 deposited in, at most, shallow water and that great areas of the 

 Appalachian basin, like other regions in which shales occur, were 

 above the area of deposition for prolonged periods. 



The Limestones and the Marine Deposits. — Four limestones, 

 with marine fauna, have been discovered in the Warrior coal field 

 of Alabama, all, except possibly the highest, in the New River ; 

 Sailford discovered a " local bed " of hard crinoidal limestone in his 

 Upper Conglomerate within Grundy county of Tennessee, also New- 

 River; M. R. Campbell found a marine fauna in southern West 

 A'irginia within the New River and D. White*^ obtained Spirorhis 

 and Naiadites in the southern anthracite field. The last is possibly 

 brackish water ; the others, distinctly marine, show that during 

 the New River salt water occasionally had access, at least locally, 



*° D. White, " Deposition of the Appalachian Pottsville," Bull. Geol. Soc. 

 Amer., Vol. 15, 1904. p. 277. 



