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Mica-Slate, Mica-Schist, Micaceous Schistus. One of the lowest 

 of the stratified rocks, belonging to the hypogene or primary 

 class, which is characterised by being composed of a large pro- 

 portion of mica, united with quartz. 



Miocene. This is the period next succeeding the eocene, and em- 

 braces a larger share of recent or living species among the or- 

 ganic remains. It is called miocene from fxsiuv, less, and xcuvo?, 

 recent, implying that the formations in question contain less 

 recent than extinct species ; or in other words, that the living 

 races are a minority. Out of 1021 shells in Europe, 176 only 

 belong to animals now living, making the proportion of the re- 

 cent species about 18 per cent. 



Mollusca, Molluscous Animals. Animals, such as shell-fish, which, 

 being devoid of bones, have soft bodies. Etym., mollis, soft. 



Mountain Limestone. A series of limestone strata, of which the geo- 

 logical position is immediately below the coal-measures, and 

 with which they also sometimes alternate. 



Muriate of Soda. The scientific name for common culinary salt be- 

 cause it is composed of muriatic acid and the alkali soda. 



New Red Sandstone. A series of sandy, argillaceous, and often cal- 

 careous strata, the predominant colour of which is brick-red, but 

 containing portions which are of a greenish-gray. These occur 

 often in spots and stripes, so that the series has sometimes been 

 called the variegated sandstone. The European formation so 

 called lies in a geological position immediately above the coal- 

 measures. 



Nodule. A rounded irregular-shaped lump or mass. Etym., dimi- 

 nutive of nodus, knot. 



Old Red Sandstone. A stratified rock belonging to the Carbonife- 

 rous group (of Europe.) 



Oolite, Oolitic. A limestone, so named because it is composed of 

 rounded particles, like the roe or eggs of a fish. The name is 

 also applied to a large group of strata, characterised by peculiar 

 fossils, because limestone of this kind occurs in this group in 

 England, France, &c. Etym., wov, oon, egg, and Xi<3o£, lithos, 

 stone. 



Organic Remains. The remains of animals and plants {organized 

 bodies) found in a fossil state. 



Orthocerata, or Orthoccrx. An extinct genus of the order of Mollus- 

 cous animals, called Cephalopoda, that inhabited a long cham- 



