Continuity of Metalliferous Repositories in Depth. 359 



continuity of minerals in depth, assuming, it is true, very 

 capricious forms, but supported by new observations. 



The zone of anthraxiferous limestone which appears in the 

 valley of the Meuse, from Huy as far as Chockier, continues 

 from Liege to Aix la-Chapelle and Eschweiler, disappears 

 towai'ds Duron under the alluviums of the Rhine, then reap- 

 pears beyond Dusseldorf, at Iserlohn and Brilon ; this zone 

 presents, towards its line of contact with the coal-forma- 

 tion slates and psammites, with which the limestone alternates, 

 a series of irregular repositories lying between the strata. 

 These repositories are filled with oxides of iron, carbonates 

 and silicates of zinc, blende, and galena ; those of Huy, 

 Engis, Moresnet, Verviers, Stolberg, have given rise to the 

 extensive fabrication of zinc in Belgium and Prussia. 



These calaminary repositories were still regarded, a few 

 years ago, as superficial remblais accumulated in pre-existing 

 cavities. This opinion resulted from some unprofitable works 

 undertaken in the expectation of finding the superficial mass 

 continued downwards ; then, upon the works being caiTied 

 on in a rational plan, it was found that the superficial masses 

 continued, not according to the seams of the stratification 

 of the formation, but by ramifications which were often com- 

 plex, sinuous, and of very variable section. The generality 

 of this continuity, established by the works of Engis and 

 Verviei's, is completely acknowledged by MM. d'Omalius 

 de Halloy and numerous practical men, among whom I may 

 mention M. Simon, director of the mining operations of 

 Nouvelle-Montagne, and M. Goschler, mining engineer at 

 Stolberg. 



The continuation of these subterranean canals in depth, 

 is effected by movements sometimes so irregular and unex- 

 pected, that we thus readily explain how the first works, 

 undertaken to determine this, have remained unprofitable. 

 Thus, for example, the continuity of the celebrated reposi- 

 tory of Moresnet (la Vieille-Montagne) has not yet been 

 ascertained, although many works on a sound principle have 

 been undertaken with this view ; but can we thence infer 

 that it is questionable \ Undoubtedly not ; and the engineers 

 who have studied the subteiTanean works of Engis, Verviers, 



