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XVIII. A Letter on the Alterations that have taken place in 

 the Structure of Rocks, on the Surface of the basaltic 

 Country in the Counties of Derry and Antrim. Addressed 

 to Humphry Davt, Esq.> Sec. M.S. By William 

 Richardson, D.D, * 



SIR, 



i. request you will be so good as to lay before the Royal 

 Society the following observations on the Natural History 

 of that part of Antrim, (contiguous to the-Giant's Cause- 

 way,) which you and I examined so carefully together. I 

 know not any country that deserves so well to have its facts 

 faithfully recorded; from the important conclusions to which 

 they lead. 



The basaltic area (taken in its whole extent) comprehends 

 the greater part of Antrim, and the east side of Derry to a 

 considerable depth. 



In a geological point of view, nature f has been very kind 

 to this district, for not content with assembling together in 

 a small space so many of her curious productions, and ar- 

 ranging them with more regularity and steadiness than in 

 any other country described, she has condescended occa- 

 sionally to withdraw the veil, and Jay herself open to view, 

 often exhibiting a spectacle equally gratifying to the admirer 

 of magnificence, and to the curious naturalist, who can 

 here, by simple inspection, trace the arrangements which 

 are to be discovered elsewhere, only by penetrating beneath 

 the surface of the earth. 



As soon as we enter the basaltic area, we begin to per- 

 ceive traces of these arrangements; as we advance further 

 north, they increase; and in the tract near the shore, and 

 especially at the island of Utithliri, which seems to have 

 come fresher from the hand of nature than the rest of our 

 area, the stratification of the whole is perfectly visible, and 



* From Philosophical Transactions for 1808. 



•J- By the word nature, which frequently occurs in the course of this Me- 

 moir, I always mean, according to Pvay's definition^ the wisdom of God in 

 the creation of the world. 



~ r-k the 



