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Lias. A provincial name, adopted in scientific language, for a 

 particular kind of limestone, which, being characterised together 

 with its associated beds, by peculiar fossils, forms a particular 

 group of the secondary strata. 



Lignite. Wood converted into a kind of coal. Etym., lignum, 

 wood. 



Lithological. A term expressing the stony structure or character 

 of a mineral mass. We speak of the lithological character of 

 a stratum as distinguished from its zoological character. Etym., 

 Xfdof, lithos, stone, and \oyo<z, logos, discourse. 



IMtoral. Belonging to the shore Etym., littus, the shore. 



Loam* A mixture of sand and clay. 



Madrepore. A genus of corals, but generally applied to all the 

 corals distinguished by superficial star-shaped cavities. There 

 are several fossil species. 



Mammillary. A surface which is studded over with rounded pro- 

 jections. Etym., mammilla, a little breast or pap. 



Mammoth. An extinct species of the elephant (E. primi genius,) 

 of which the fossil bones are frequently met with in various 

 countries. The name is of Tartar origin, and is used in Siberia 

 for animals that burrow under ground. 



Marl. A mixture of clay and lime ; usually soft, but sometimes 

 hard, in which case it is called indurated marl. 



Mastodon. A genus of fossil extinct quadrupeds allied to the 

 elephant. So called from the form of the hind teeth or grinders, 

 which have their surface covered with conical mammillary 

 crests. Etym., \i.a.<fros, mastos, pap, and oduv, odon, tooth. 



Matrix. If a simple mineral or shell, in place of being detached, 

 be still fixed in a portion of rock, it is said to be in its matrix. 

 Matrix, womb. 



Mechanical Origin, Rocks of. Rocks composed of sand, pebbles, 

 or fragments, are so called, to distinguish them from those of a 

 uniform crystalline texture, which are of chemical origin. 



Mica. A simple mineral, having a shining silvery surface, and 

 capable of being split into very thin elastic leaves or scales. 

 It is often called talc in common life, but mineralogists apply 

 the term talc to a different mineral. The brilliant scales in 

 granite are mica. Etym., mico, to shine. 



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