7 6 OFSTONES. 



A variety of the coralloid fpecies, with deep pori, compofed 

 of arenaceous granules, and fmall cryflals, incapable of a po- 

 liture, when rubbed down, is not uncommon on the eaflern 

 fliore of North Tyne, by its OJiium ; and alfo on the more of South- 

 Tyne, but more rarely ; the pori of the latter often extending 

 near the whole length of the columns, glittering with corpuf- 

 cles, or fpangles, of cryftal. 



Thefe aftroite coralloid Pori are formed fo much like a Honzy- 

 comb, that they have obtained the name of Honey comb~&onea. 



Single columns of madrepore-coralloids, both cylindric, and 

 branched, of various fizes, are not unfrequent in the clay-banks 

 by the brook at Slmonburn, above the bridge, on the north fide. 



Of the former fpecies, I met with a remarkable variety, grey, 

 of a folid and firm texture, flriated lengthways, a little inflected 

 and comprefled, with a broad furrow, towards the extremity, 

 with white arbufcular flrias on a grey ground from the center to 

 the circumference. It is an inch long, and as much round, the 

 compreffed end broken off. 



Alfo of the other I met with one as remarkable ; tuberated at 

 the ends, with Tuber a on the furface, and numerous minute pori, 

 forming an elegant reticular work of a bright white on a black 

 ground; the tubes filled with an indurated argillaceous earth, 

 of a greyifh-black ; tranfverfe alternate ilrise of black and white 

 from its edges to the circumference. It is found of different 

 fizes, from a quarter of an inch to half an inch in diameter, and 

 an inch or more in length, filled with indurated clay-earths of 

 different tinges. It is fo tender in the flrata, that I have never 

 been able to take it out with the branches entire, yet, when it 

 has been expofed to the air, grows as hard as a marble. 



Arbuf- 



