16 Mr. Weaver on the [July, 



small beds of a few inches thick, in general situated near the 

 surface. The coal is nearly always immediately covered, and 

 also sometimes divided into two beds, by a limestone of a dull- 

 yellow or blackish-brown, or presenting different mixtures of 

 these two colours ; so that in numerous mines the coal and 

 limestone are worked together. Bituminous schists have also 

 been observed in this formation, sometimes presenting impres- 

 sions of fish penetrated with sulphuret of mercury. On its 

 north-eastern limit the coal formation is covered in the environs 

 of Alzey by horizontal limestone, which extends on the N and 

 E to the banks of the Rhine ;" belonging, as it appears, to the 

 formations posterior to the chalk. 



The preceding description by M. de Bonnard shows distinctly 

 that in the tract which forms the subject of his memoir, we have 

 the old red sandstone supporting two coal basins ; in the north- 

 ern of which, or that of the Glane, the carboniferous limestone 

 not only appears in many places forming the immediate base of 

 the coal formation, but is also interstratified with the coal mea- 

 sures, then commonly serving as the immediate roof of the coal. 

 In the southern, or the Sarre coal basin, on the other hand, the 

 carboniferous limestone occurs only between the upper strata of 

 the coal measures. Now, this extensive carboniferous series is 

 distinguished on M. Omalius d'Halloy's map, and in his memoir 

 as the todte liegende or ancient red sandstone group, including 

 the coal measures, quite in conformity with the German sense 

 of that term.* Indeed Mr. De la Beche himself cannot avoid 

 admitting (see the note, p. 223), that the old red sandstone sup- 

 ports the coal measures of the Palatinate, thus invalidating his 

 own position on the map and elsewhere, that the todte liegende, 

 or rothe liegende, group denotes a new red sandstone conglome- 

 rate. I think it needless to point out the repeated instances of 

 this misconstruction of the term in other parts of the work, 

 since what has been said admits of general application. I will, 

 therefore, merely add, that in thus applying the term new red 

 sandstone conglomerate to the ancient red sandstone group of 

 Werner (which includes the coal tracts), a violence is done to 



* See the construction of Freiesleben and of other German authors on this subject in 

 the Annuls of Philosophy for Aug. 18*22, and May, 1823. 



See also the memoir of M. von Hoffin Mr. De la Beche's Selection, p. 92, where, 

 after describing the primary and transition rocks of the Thuringerwald, he proceeds 

 thus: — " Those conglomerates, and micaceous or quartzose red sandstones {conglomerate 

 rothes und graves liegende), which together compose the formation named red sandstone, 

 considered the most ancient of the secondary (floetz) formations, are the most extensively 

 spread of all the rocks in the Thuringerwald ; " and p. 93, " The coal formation of 

 the Thuringerwald appears to belong, as a subordinate member, to the preceding." 



If we combine also the valuable description given by 31. de Bonnard, of the primary 

 and transition tracts of the Hartz (p. 202 — 273 of the Selection), with Freiesleben's 

 account of the carboniferous series of the Hartz and the adjacent districts (as abstracted 

 by me in the numbers of the Annals of Philosophy referred to above), the geological 

 succession of the primary transition, and carboniferous series, will be found as obvious 

 there as it is in M. von HoflPs description of the Thuringerwald. 



