1858.] 



HAEKNESS DOLOMITES . 



101 



quarry tkree very distinct masses of yellow magnesian Hinestone are 

 seen. One of these masses is represented in fig. 10. The bedding 



Fig. 10. — Dolomitic Carboniferous Limestone, at Gasiuorlcs Quarry, 



Corlc. Looking South. 



The central Hght- tinted rock is dolomite 



of the whole of the strata in this quarry, as before mentioned, is very 

 rudistinct ; but the general strike of the beds supports the conclu- 

 sion that the strata have an east and west range ; and, consequently, 

 the iacHnation of the strata must be either north or south, unless 

 they be vertical. This arrangement of the stratification would lead 

 us to expect that the dolomites would strike east and west also, 

 parallel to the ordinary limestone-strata, had these dolomites ori- 

 giuated from the same circumstances which have given rise to the 

 other limestones. So far is this from beiug the case, that we have 

 the dolomitic masses striking north and south ; and, as the jointing 

 is weE. developed in this quarry (more especially the north and south 

 joints), we find an intimate agreement between the direction of the 

 joints and the courses which these masses of dolomite assume. 

 These features, as to direction, are not confined to the Gasworks 

 quarry ; the same phenomena are apparent at the larger quarry at 

 Sunmierstown, also previously referred to (p. 92), and here likewise 

 the jointing is weU developed. 



Hand-specimens can be obtained which exhibit the intimate con- 



