MINEKALOGY. 



495 



Kongiberg in Norway : al*o in transition alum-slate in 

 larger and smaller elliptical masses, the centre of which 

 is of iron-pyrites, and the periphery sparry lucullite, at 

 Andnrum in Sdionen, Garphytta in Nericke, and 

 Christiania in Norway. 



ELEVENTH SUBSPECIES. 

 MARL, Jameson. Mergel, Werner. 



This subspecies is divided into two kinds, viz. Earthy 

 Marl and Compact Marl. 



First Kind. 



EARTHY MARL, Jameson. Mergel Erde, Werner. 



External Characters. Colours yellowish-grey, and 

 seldom pale smoke-grey. These are the colours it ex- 

 hibits when dry : when moist, and in its original repo- 

 sitory, its colours are pale blackish-brown or brownish- 

 black *. Consists of fine dusty particles, either loose or 

 feebly cohering. Is dulL Particles feel fine, or rather 

 rough and meagre. Soils slightly. Is light. 



Chemical Characters. It effervesces strongly with 

 acids. It emits a strong urinous smell when first dug 

 up ; but after exposure to the air it loses this quality. 



Constituent Parts. It is said to be composed of lime, 

 alumina, silica, and bitumen. Friedcben. 



Gtogmutic and Geographic Stiuati>uu. It occurs in 

 beds in floetz or secondary limestone and gypsum 

 formations, along with stinkstone, in Thuringia and 

 Mansfeld. 



Second Kind. 



COMPACT OH IVDURATED MARL, Jameton. Verhar- 

 teter Mergel, Werner. 



External Charicters. Colours yellowish-grey, smoke. 

 grev, and muddy Mni.h-grey. Sometimes spotted red- 

 dish and brownish in the rents, and marked with den- 

 dritic delineations. Occurs massive, in blunt angular 

 pieces, vesicular, in flattened balls ; and frequently con- 

 tains petrifactions of fishes and crabs, also of gryphites, 

 belemnites, chamites, pectinites, ammonites, terebratu- 

 lite*, ostracites, musculites, and mytulites. Dull both 

 externally and internally, and only glimmering when 

 intermixed with foreign parts. Fracture generally 

 earthy, which approaches sometimes to splintery, some- 

 times to c-onchouLil ; in the great inclines to thick and 

 straight slaty. Fragments angular nnd blunt-edged, 

 ami sometimes tabular. Yields to the nail. Is opaque. 

 Affords a greyish-white streak. Rather brittle, and 

 . Feels meagre. Specific gravity 2.365, 

 2.550, Krnlhaujtt. 



Chemical Characters. Before the blowpipe it intu- 

 mesces, and melts into a greenish-black slag. It effer- 

 vesces briskly with acid-,. 



Const. J'osfr_Carbonate of Lime 50 



Silica, . . 12 



Alumina, . . 32 

 Iron and Oxide of Man- 

 ganese, . . a Kir if an. 

 Geagnoslic Situation It occurs in beds in the se- 

 condary floetz limestone and coal formations ; also in 

 the new secondary formations that rest upon chalk. 



Geographic Situation It frequently occurs in the 

 coal formation in Scotland and England, and in the se- 

 condary formations which rest upon chalk in the south 

 of England. 



Utet Several different kinds of compact marl oc- Oryctogno- 

 cur in nature : these are calcareous marl, in which the 

 calcareous earth predominates : clay marl, in which the V ^"Y" 111 

 aluminous earth is in considerable quantity ; and ferru- 

 ginous marl, in which the mass contains a considerable 

 intermixture of oxide of iron. The latter kind occurs 

 in spheroidal concretions, called seplaria or liidi Hel~ 

 montii, that vary from a few inches to a foot and a half 

 in diameter. When broken in a longitudinal direction, 

 we observe the interior of the mass intersected by a 

 number of fissures, by which it is divided into more or 

 less regular prisms, of from three to six or more sides, 

 the fissures being sometimes empty, but oftener filled 

 up with another substance, which is generally calca- 

 reous spar. From these septaria are manufactured that 

 excellent material for building under water, known by 

 the name of Parker's Cement *. The calcareous and 

 aluminous marl are used for improving particular kinds 

 of land ; also for mortar ; in some kinds of pottery ; 

 and in the smelting of particular ores of iron. 



TWELFTH SUBSPECIES. 



BITUMINOUS 'MARL-SLATE, Jameton. Bituminoser 

 Mergelschiefer, Werner. 



External Character*. Colour intermediate between Biiumi- 

 greyish-black and brownish-black. Occurs massive, nout marl- 

 and frequently contains impressions of fishes and plants. "lite- 

 Lustre glimmering, glistening, or shining, and resinous. 

 Fracture straight, or curved slaty. Fragments slaty in 

 the large, but indeterminate and rather sharp angular 

 in the small. Is opaque. Shining nnd resinous in the 

 streak. Soft, and feels meagre. Rather sectile, and ea- 

 sily frangible. Specific gravity 2.631, 2.690, Brett hatijit. 



Conilttuent Parts. It is said to be a carbonate of 

 lime united with alumina, iron, and bitumen. 



Geognotlic Situation. It occurs in secondary or floetz 

 limestone. It frequently contains cupreous minerals, 

 particularly copper-pyrites, copper-glance, variegated 

 copper-ore, and more rarely, native copper, copper 

 green, and blue copper. It contains abundance of pe- 

 trified fishes, and these are said to be most numerous 

 in those situations where the strata are basin-shaped. 



Geographic Situation. Europe. It abounds in the 

 Hartzgebirge ; also in Magdeburg and Thuringia. It 

 is a frequent mineral in Upper and Lower Saxony : it 

 occurs also in Franconia, Bohemia, Bavaria, Silesia, 

 Suabia, Hesse-Cassel, and Switzerland. 



America. It ia said to occur in the Cordilleras of 

 South America. 



III. SHORT-AXED LIMESTONE, on DOLOMITE. Kur- 

 zaxigcs Kalk-Haloide, Moht. 



Rhomboid = 107 22'. Cleavage rhomboidal. Hard- 

 ness ss 4.0, *.5, sp. gr. = 3.0, 3.2. 



This species contains three subspecies, viz. 1. Do- 

 lomite ; 2. Miemite ; 3. Brown Spar. 



FIRST SUBSPECIES. 



DOLOMITE, Jameton. 



This subspecies is divided into three kinds, viz. Dolomite. 

 Granular Dolomite, Columnar Dolomite, Compact Do- 

 lomite. 



Some of the rarictiet bare generally a brown colour, and emit an urinous ttnell ; these are by wine authors considered at Earthy 

 Sttnkjtone. 



+ That Mrly uptaria abound in the Iile of Shepey. 

 Mr. knio* tiTerging obraaa ancrctiooa. " 

 fanuea an nUed with quartz. 



lie 01 nuepey, in the Medway, and often contain in their .interior globular portion! ( heavy- 

 Similar Kptaria occur in DerbyJurc, and in the county of Durham, in which Utter district, 



