On the Excitement of Voltaic Piates. 165 



2. The isolated and highly elevated stratified hummocks, found 

 in many countries, and especially in basaltic districts. 



3. Whyn dykes, very lately brought into notice, but now burst- 

 ing upon us in different parts of the world, in the form of walls 

 of terrific altitude, and most regular construction. 



4. Caverns, so abundant, e'<pecially on the confines of sea and 

 land, and in calcareous districts, grand and beautiful grottoes, 

 bearing irresistible marks of po'.terior excavation, not to be ex- 

 ecuted by any agents with wiiich we are acquainted. 



5. The line of demarcation between sea and land, and the for- 

 mation of the basin of t'.ie ocean. 



It has pleased Nature to lay bare the northern district of 

 Antrim, and I may say its whole coast, to disclose her secrets to 

 us, and to expose her arrangements to the naked eyej it is in 

 our magnificent facades, so numerous, and so kindly extended 

 along a great line of coast, that we are enal)led to distinguish 

 between original formation and posterior operations ; and to 

 pronounce upon the quiet state in which these original materials 

 liave remained since their final consolidation ; notwithstanding 

 the numerous revolutions and convulsions so confidently ob- 

 truded on us. 



I shall in my next request your ladyship to accompany me 

 to a new field, where the original arrangements of Nature seem 

 to be the same with those in Antrim, and where posterior opera- 

 tions also bear a strong resemblance, and of course where my 

 arguments drawn fiom facts receive further confirmation ; I 

 mean the island of St. Helena, upon which the attention of the 

 Avorld has been lately much fixed from causes unconnected with 

 its natural history. 



I am, with much respect, 



Your ladyship's most obedient humble servant, 



Clonferle, Moy, W. RiCHARDSON, D.D. 



February 2j, 18 1 6. 



XXXVI. On the Excitement of Voltaic Plates ; in Repli/ to 

 Air. I)n Lrc's Ohjections to the Doctrines maintained by the 

 Author. By J. U. Maycock, M.D. 



To Mr, Tilloch. 



IBarladocs, May 23, 181(5. 

 UF.G to convey to Mr. Do Luc my apology for not 

 having noticed at an earlier period his observations on two pa- 

 pers, which Mr. Nicholson did ine the favour to publish in his 

 valuable Journal*. In July 1S12, I left England for the West 



* Pliil. Journal, vol. xxix. and xixi, 



L 3 Indies^ 



