VDt. XVMI.] PHILOSOPHICAL TRANSACTIONS. 657 



SO close one to another, that a knife can hardly be thrust in between their 

 sides ; and though some have 5 sides, and others of them 6, yet their contex- 

 ture is so adapted, that there is no vacuity between them : the inequality of the 

 numbers of the sides of the pillars being often in a very surprising and won- 

 derful manner, throughout the whole causeway, compensated by the inequality 

 of the breadths and angles of those sides ; so that the whole at a little distance 

 looks very regular; and where in many places a good number of the pillars are 

 exactly of the same height, the superficies of their tops looks very like the 

 pavements that are in some gentlemen's halls. Every single pillar retains its 

 own thickness, and angles, and sides, from top to bottom. Those which seem 

 to be entire, as they were originally, are at the top fiat and rough ; those which 

 lie low to the sea are washed smooth ; and others, that seem to have their 

 natural tops blown or washed off, are some concave, and others convex. 



Some Notes on the foregoing Account of the Giant's Causeway, serving further 

 to illustrate it. By T. Molyneux, M. D. S. R.S. N° 212, p. 175. 



Among the several figured stones already described by authors, I find none 

 that has more agreement with those that compose our Giant's Causeway, than 

 the entrochos, the astroites, or lapis stellaris, and the lapis basanus, or basaltes; 

 and yet they differ very much in some particulars. The entrochos agrees with 

 the pillars of our Causeway in that it is a stony substance, formed by nature 

 columnwise, and consisting sometimes of 20 or 30 several internodia, or joints 

 set on each other ; but then it differs in that its outward shape is round and 

 cylindrical, in its having a hole or pith run from top to bottom through all the 

 joints, in the setting on, or way of fitting one joint to another, and in its size 

 and magnitude. 



But the make of the astroites, or lapis stellaris, seems to have still a greater 

 affinity in its formation with our Irish stones ; for it is not only shaped column- 

 wise, as the entrochos, and jointed with several internodia closely adjusted to 

 ' one another, but its sides are angular, and the manner of the commissures of 

 one joint to another, in some particulars, more resembles the way nature ob 

 serves in jointing this stone. It must be observed, that the sides of the astroites 

 are always sulcated, or a little furrowed, and are constantly pentagons ; whereas 

 the Irish stone has its sides perfectly smooth, and plain, and sometimes in 

 hexagons and heptagons, as well as pentagons. 



But the astroites also, as well as the entrochos, differs extremely from our 

 stone, in its size or magnitude ; for the largest that is found of either of those 

 kinds do not much exceed the thickness of a man's thumb, whereas our 



VOL. III. 4 P 



