•bula/ basalt is;(th(3 stones, and tb^; urtformed the cejnent. 



I have- great I reast)^ to :' bejieve, that -the .varieties of 



basalt, in other , Gouptries, are exactly, the sJime as in our 



ovivji and that ' JJiature^ lia^ (taken the same pains to keep 



tjjeipv distinct every AvheK^.,,.;. ■ , 



vl^^i.9,ipt||jiiijpaf; t),asal|;;i ^i; all countries, , corresponds pre- 

 cisely, jwith tlja^^, of t^, Giant's Cajiseway, and our other 

 groups, as appears fro^n tjie sameness of their curious articu- 

 lations:,.y^Q(^.403.,v5 ,3gj3jjg(u;I a'bno'i ..■ 



Our- irregular prisfliatic evxact,ly answers the descriptio 

 of the basalt, incumbent on the columnar at Bolsena, as 

 gh'en by Ferber. It is obviously similar to those at La 

 Trezza and Pont dii Baume; and Mr. Mills's view of the 

 isolated basaltic rock, 'at ^iA:i^dfti'n' (Phil. Trans. 1790), ac- 

 curately representSiJthi^i.yaj-ie^y^ia.iinany facades, near.the 

 Gi'ant's CauseAvay. ^^ ■ "' 1'": • •'•'•■J "■ ■' '"^ ■ 



Sir Joseph BankS's''£l'6'bdurit' Of.tlie stratum, incumbent 

 on tlie .cf>luninar, Jit ^t^ffa, migfet, serve, for our irregulai- 

 prismatic, in most ^-^jfifeiGesj -and, the moment I shcMcd 

 my frrend;' Mr.' Joy;' •om'''iieat pillars .at Craigahuller, he 

 perceived the striking lilven^ss, l^e^ween the stratum, in- 

 cumbent on them, land' that c'avcring the grand colonnade 

 at Staffa. ' • "''' 



' \''i:\l^%ig)[ii^'tlc^om^^ ,%otch whyn dykes, 



shew, that they are formed, likei.pur: own, of horizontal 



prisms."'-''"'^ il:jili.' (li Olr.'.r' otlj ^iri WSitj'j'! ill.c; 1. 



And our globular basalts, with concentric spheres, so cu- 

 riously imbedded, as we; find them, at Port Cooan, near 

 the Giant's iCauseway, and lining some whyn dykes, at 



■fo s.iol ai<i jiio Belfast 



