.-* 









M 







CANADIAN ROCKS. 



253 



250. 



Porphyritic greenstone, composed of imperfect 



of felspar, in a base of compact greenstone 



Opposite Ramsey Sound, St. David's, Pembrokeshire. 



251.— Amygdaloid, with crystals of quartz replacing 

 calc spar.—East of Bettws Disserth, Radnorshire. ° 



large kernel of calc 



252. 



Amygdaloid, containing a 



spar.— Lower Ridge, li mile east of Chirburj, Salop. 



253.— Vesicular greenstone (« toadstone "), the air- 

 vesicles, originally formed when the rock was in a fused 

 state, have been filled with kernels of calc spar, which last 

 were subsequently removed by the percolation of water. 



Matlocl 



254. 



Serpentinous greenstone. 

 Wotton-under-Edge, Gloucestershire. 



Damory Bridge, 



255. 



Trappean conglomerate, composed of fragments 



arenaceous cement 



) 



of quartz, sandstone, and slate in an 



chiefly, and associated with grey argillaceous slatesfTsee 

 "Report on Cornwall," pp. 120 and 121. Dc 



Cam Mere Point, near Nare Head, Cornwall. 

 256. 



257. 



258. 



259. 



Upper 

 G allery. 



"Wall -case 

 6 and 7. 







Canadian Specimens, &c* 

 260. — Felsite porphyry (Euritique, &c), part of a 



bould 



Montreal 



261 — Gnetssoid rock, containing garnets. — La Prairie 

 near Montreal, Lower Canada. ' 



262. 



Quartz (fi 



crystals of 



garnet. From a boulder— Banks of the St. Lawrence, 



Mont 



263.— Part of a granite boulder, containing numerous 



garnets.— Banks of the St. Lawrence, Montreal, Lower 

 Canada. 



American rocks, chiefly presented by Sir William Logan. 



