1824.] Older Red Sandstone Formation, §c. 21 



and designated in England as the millstone-grit, is wanting in 

 Ireland. 



N. B. This peculiar application of the term millstone-grit is 

 bad as a distinction, since a similar compound is generally found 

 in beds in the fundamental or old red sandstone, and in some 

 countries also frequently interstratified with the coal measures, 

 e. g. in Germany. 



2. A base of old red sandstone, supporting limestone, which 

 alternates with sandstone, a considerable bed of the latter, with 

 conglomerate, forming the immediate foundation of the coal 

 measures, which are distinct ; e. g. the Gloucestershire south 

 coal basin. 



N. B. The more common coal bearing measures are in this 

 basin separated into a lower and an upper series by an interven- 

 ing thick bed of reddish sandstone, locally known by the name 

 of Pennant-stone. 



N. B. A similar occurrence, on a larger or smaller scale, is not 

 uncommon in Germany, and when the red sandstone thus occurs 

 immediately under the magnesian or alpine limestone (with its 

 calcareous or new conglomerate, the tceissliegende), it is known 

 by the name of todte liegende, or rothe liegende, or rothe todte 

 liegende, in the same manner as these terms are applied to the 

 fundamental red sandstone when also directly covered by the 

 calcareous conglomerate and magnesian limestone. But the 

 term rothe todte liegende has also been often erroneously 

 applied, as already noticed above, to the calcareous or new con- 

 glomerate itself.* 



3. A base of old red sandstone, supporting and alternating 

 with some beds of limestone, succeeded by a coal formation, 

 composed, in an ascending order, as follows : 



a. Of coal measures alternating with limestone, and with red- 

 dish sandstone, the coal being inconsiderable in quantity. 



b. Productive coal measures, alternating with numerous beds 

 of limestone. 



* M. von Humboldt correctly distinguishes the weissliegende, as the bed which 

 intervenes between the coal formation and the zechstein, or magnesian limestone (see p. 

 22-4 of the Essai). It thus corresponds with the calcareo-magnesian, or new conglome- 

 rate of England, appearing as its only representative. 



On the other hand, however, both M. von Humboldt and Dr. Boue speak of the 

 zechstein, or magnesian limestone, as occurring sometimes interstratified witli the coal 

 measures. This is a position utterly at variance with all experience in the British Isles, 

 and seems quite untenable, if we consider that the calcareous conglomerate, or weisslie- 

 gende, is commonly found in an unconformable position, overlying both the coal 

 measures, and the carboniferous series in general ; being the first member of a new 

 series ; namely, of the gypseo-saliferous. In the instance quoted, e. g. in Lower 

 Silesia (p. 34, 213, &c.) it is true that, in the year 1802, M. von Buch considered the 

 limestone in question as zechstein, and as such as of an origin posterior to, and placed 

 above the coal formation ; but M. von Kaumer in 1819 clearly showed that this lime- 

 stone was repeatedly interstratilied with the coal measures, and therefore not zechstein ; 

 and certainly no two scries can be generally more distinct from each other than the car- 

 boniferous and the gypseo-saliferous series. < Hlicr instances cited, probably rest upon 

 no securer foundation than misconception, or fallacious description. 



