Dr J. W. Dawson 07i the Antiquity of Man. 47 



a country. Among the sections obtained by quarrying, one 

 of the finest which I saw was in the beautiful valley of 

 Fond du Foret, above Chaudefontaine, not far from the 

 village of Magnee ; where one of the rents communicating 

 with the surface has been filled up to the brim with rounded 

 and half-rounded stones, angular pieces of limestone and 

 shale, besides sand and mud, together with bones, chiefly of 

 the cave bear. Connected with this main duct, which is 

 from one to two feet in width, are several minor ones, each 

 from one to three inches wide, also extending to the upper 

 country or table-land, and choked up with similar materials. 

 They are inclined at angles of 30° and 40°, their walls being 

 generally coated with stalactite, pieces of which have here 

 and there been broken off and mingled with the contents of 

 the rents, thus helping to explain why we so often meet 

 with detached pieces of that substance in the mud and 

 breccia of the Belgian caves. It is not easy to conceive that 

 a solid horizontal floor of hard stalagmite should, after its 

 formation, be broken up by running water ; but when the 

 walls of steep and tortuous rents, serving as feeders to the 

 principal fissures, and to inferior vaults and galleries, are en- 

 crusted with stalagmite, some of the incrustation may 

 readily be torn up when heavy fragments of rock are hurried 

 by a flood through passages inclined at angles of 30° or 40°. 



" The decay and decomposition of the fossil bones seem 

 to have been arrested in most of the caves by a constant 

 supply of water charged with carbonate of lime, which 

 dripped from the roofs while the caves were becoming gradu- 

 ally filled up. By similar agency the mud, sand, and pebbles 

 were usually consolidated. 



" The following explanation of this phenomenon has been 

 suggested by the eminent chemist Liebig. On the surface 

 of Franconia, where the limestone abounds in caverns, is a 

 fertile soil in which vegetable matter is continually decay- 

 ing. This mould or humus, being acted on by moisture and 

 air, evolves carbonic acid, which is dissolved by rain. The 

 rain-water, thus impregnated, permeates the porous lime- 

 stone, dissolves a portion of it ; and afterwards, when the 

 excess of carbonic acid evaporates in the caverns, parts with 

 the calcareous matter and forms stalactite. So long as 



