published respectivg Antrim, Dernj, &c. 275 



and Derrv are probably very variable and considerable, and 

 the same is a proper subject of further elucidation in your 

 Magazine, as a work prettv generally and increasingly read 

 by Geological inquirers. Dr. W. H. Driimmond, preface 

 p. viii. gives the following account of the strata above the 

 thin lavtr ot bituminous schist, alreadv mentioned p?ge 

 272; this is overlaid, says he, '' by a Ibie Limestone con- 

 tainini{ the Star-stone, or vertebrae Pentacrinifes, Cornu 

 ammonis, and Anomia gryphus. To this succeeds a stra- 

 tum of arenaceous IJmestone, often of a green hue, known 

 in this district by the very appropriate name of Mulatto, 

 from its mixed nature, and the difference of its colour from 

 the snow-white Limestone, by which it is covered. This 

 stratum abounds in quartz pebbles (or coarse grains of 

 silex, rather ?) and organic remains, particularly £e/e/«/7?i(?5*, 

 Pecfenites Ldiini, Osiracites^ Carclia, Anemia gnjphtis, 

 and a substance resembling Gypsum, which some suppose 

 to be the Pinna marina, so closely conglomerated and 

 united by the arenaceous paste, that they seem in some 

 places to compose almost the whole mass. 



"Above the mulatto lies a very thick stratum of white 

 Limestone, one of the purest carbonates of Lime, also con- 

 taining Belemnites in abundance, Cardia more rarely, with 

 Flints, ranging in horizontal lines, and often, where it is 

 traversed bv a dyke, exhibiting a granular structure like 

 Jllarble. The horizontal lines of its stratification being cut 

 by vertical fissures, it has frequently the appearance of 

 huge quadrangular blocks, artificially built on each other," 

 page ix. And he continues, " One of the most remark- 

 able appearances, which will next arrest the observer's at- 



* The Belemniie zviA Eihinus are often found in flint. The former, when 

 found either in limestone or mulatto, is generally of a yellow, calcareous, 

 sparry texture on the outside, the centre being of the same substance as that 

 in which it is Inibeddi'd. From some specimens of the Kthinvs which I 

 broke, ir appears, that they are a solid mass of the same material as that in 

 which they lie, and contain no central crystallization: but the place of the 

 shell in flint is marited by a very thin sparry incrustation. In the mulatto 

 tlie shell is very distincily preserved; it has become of a sparry texture; is 

 much thicker than that nf the urchin, now found in our Seas; has no ap- 

 pearance of an opening; having ever been at the top, but of two small orifices 

 near each It. ngitudinal extremity of the base, by which the matter was in- 

 jected. St. Pierre in liis IVih Study of Nature observes, "that many of 

 the cormi ammtjois and single-shelled fossils, which from ihcir form have 

 resisted the pressure of ttie ground, have not ejected their animal matter, 

 but exhibit it within tlum under tht form of crystals, whereas the two- 

 khelled are totally destitute ot it." 'the observation will apjily sometimes 

 to I he cornu ammonis, not to the Echinus, as far as my observation extends. 

 To the above list, add the Mi/tilus crista galli, the Dntlalium,Arcn,TcUma, 

 and Urtpula, lound in Collin- Glen by Mr. Tetnpleton." 



tcntion. 



