CONTENTS. 



VIII. I^ciiiarh on the Vitrifcd Forts of Scotland. 5y J. Mac CuUoch, 

 M.D. F.L.S. Chemist to the Ordnance, and Lecturer on Chemistrr/ 

 at the Roj/al Militari/ Academy at TVoolzoich, and Vice-President 



of the Geological Society . p. 255 



IX. On the Sublimation of Silica. By J. Mac Cullocli, M.D. F.L.S. 



Chemist to the Ordnance, and Lecturer on Chemistry at the Royal 

 Military Academy at JVoolaich, ar.d Vice-President of the Geological 

 Society. ' p. 275 



X. Observations on the Specimens o/ Hippurites ^"om Sicily, presented 



to the Geological Society by the Hon. Henry Grey Bennet. By 

 James Parkinson, Esq. Member of the Geological Society. p. 277 



XI. An Account of the Coalfield at Bradford, near Manchester. By Robert 



Bakevvell, Esq. communicated to the Society by Dr. Roget, Member 



of the Geological Society. p. 282 



XII. So)ne account of the Island of Tcneriffe. By tlie I[on. Henry Grey 

 Eennet, M.P. F.R.S. and President of the Geological Society. p. 286 



XIII. On the Junction of Trap and Sandstone, at Stirling Castle. By . 

 J, Mac Culloch, 31. D. F.L.S. Chemist to the Ordnance, and Lcclurcr 

 on Chemistry at the Royal Military Academy at TJ oolwich, and Vice- 

 President of the Geological Society. p. 305 



XIV. On the Economy of the Mines of Cornxn^ull and Devon. By John 

 Taylor, Esq. Member of the Geological Society. . p. 309 



XV. On the Origin of a reir-iarlaible class of Organic Impressions occur- 

 ring in Nodules of Flint. By the Rev: William Conybeare, of 

 Christ Church, Oxford, and Member of the Geological Society. p. 328 



XVI. A Description of the Oxyd of Tin, the production of Cornzoall ; of 

 the Primitive Crystal and its Modifications, including an attempt to 

 ascertain zcith pi ecision, the admeasurement of the a;?glcs, by mcayis 



.. of the reflecting Goniometer of Dr. TVollaston : to ichich is added, 

 a series of its crystalline funns and varieties. By William Phillips, 

 Esq. Member of the Geological Society. . . p. 33Q 



