42 



CONGLOMERATES 



"UPPER 



Gallery. 

 , r all-casc41. 



10. 



Swansea, Glamorganshire. 



Measu 



Town Hill, 



11— Permian conglomerate, composed of rounded 

 waterworn pebbles of sandstone, quartz, and limestone in 



a sandstone base. 



Warwicksh 



12. — Conglomerate of rounded waterworn pebbles of 

 quartz in a sandstone base, from Old Red Sandstone.— Mit- 

 cheldean, Gloucestershire. 



13. —Conglomerate composed of Oolite fossils and small 

 black pebbles in a calcareous base, from Lower Green Sand. 

 — Farringdon, Berkshire. 



14 — Polished conglomerate, (Pudding stone,) composed 

 of flint pebbles in a siliceous cement. — Hertfordshire. 



Conglomerate of small pebbles of black flint, in a 



15 



Whiting 



Presented by the Tidal Harbour Commissioners. 



16. — Breccia, composed of angular fragments of granite, 



Dublin 



fi 



the 



Q 



The limestone belongs to the " calp" or middle part of 

 the Carboniferous limestone of Ireland, and is burned for 

 lime. " The Crumlin quarries are four miles from the foot 

 of the present granite hills, but, similar fragments of granite 

 are found in the limestone at one or two intermediate spots. 

 These fragments were, probably, carried in the roots of trees, 

 or other plants, swept from the old granite islands into the 



surrounding seas, 



during the carboniferous period. 



?? 



In 



of accounting for 



corroboration of the foregoing mode 

 the occurrence of granitic fragments in the limestone, 

 Mr. Jukes further states that "the only hard stones 

 possessed by the natives of the coral archipelago of 

 the Marshall Islands, in the North Pacific, are similarly 

 thrown ashore in the roots of trees swept from the rivers of 

 Asia, or North America, several thousand miles off." 



17. 



Pt 



pebbles. This is from a different set of beds from the 



Shrewsbury, Salop. 



Nos 



Holling 



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