Gculogy and Geogi-npliij. 377 



uiuIpi- consideraiion, with tl'.e exception of a few local variations, 

 whicli can be easily explained, also attests the action of currents 

 from the west and north-west. Mr Bryce next spoke of the 

 niagnesian limestone of Cultra, near Hollywood, in the county 

 of Down, which he remarked occurs within a space about a mile 

 long and a few inches broad. It is fine grained and compact, 

 and is generally of a grey or bluish-grey colour. It alternates 

 in thin layers with strata of sandstone, which there cati be no 

 doubt is the lower portion of the new red sandstone series. A 

 bluish-black shale, of a soft and friable texture, and unctuous 

 feel, but destitute of bituminous matter, is associated with the 

 sandstone in some places, and seems to be inferior to the lime- 

 stone ; it effervesces feebly with acids. The beds of sandstone 

 below the limestone are often conglomerated in their structure, 

 and are interstratified with a conglomerate containing frag- 

 ments of quartz, grey wacke, with a yellow earthy and a grey crys- 

 talline limestone imbedded in a slightly calcareous base. To 

 these greywacke slate succeeds. The conglomerate and sand- 

 stone below the limestone agree very closely in character with 

 the calcareous conglomerate of the west of England, and the 

 " inferior red sandstone" of Professor Sedgwick, which underlies 

 the magnesian limestone of the east of the same country, and 

 which that distinguished geologist has identified with the " Rothe 

 Todliefrende"' of Germany. The calcareous blue shale alluded 

 to seems beyond doubt the equivalent of the " marl slate" or 

 " kupferschiefer,''" the compact bluish-grey limestone to hold 

 the place of the " Zechstein," while the upper red sandstones 

 or gypseous marls of the vicinity of Belfast are the types of the 

 " keiiper and bunter sandstein," the muschelkalk being absent 

 in Irtlatul as in England, and the rauchwacke being represented 

 onlv by a partial and unimportant yellow limestone. Mr Bryce 

 remarked it was a remarkable instance of the uniformity of for- 

 mations, that there should occur in an insignificant spot, rather 

 less than a mile long and only a few inches broad, a series of 

 beds, which seem the exact equivalents, in relative position and 

 mineral structure, of depo.-its which occupy in the east of Eng- 

 land a space 200 miles long and (rom tm to forty broad, and on 

 the continent of Europe are t-till more extensive. ]\Ir Bryce 

 tlien alluded lo several ( ther points connected with tlie geology 



