MIL 



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M I 



than in madrepores, and do not 

 exhibit any star-like radiations. 



MILLE'POEITE. A fossil millepore. 



MILI'OLA. | A genus of microscopic 



MILLI'OLA. ) multilocular univalves, 

 not larger than a millet seed, with 

 transverse chambers, involving the 

 axis alternately, and in three 

 directions ; the opening small and 

 circular, or oblong, at the base of 

 the last chamber. Several species 

 are found to exist on our shores. 



MI'LIOLITE. \ The fossil Miliola. So 



MI'LLIOLITE. ) numerous are these 

 minute fossils in the neighbourhood 

 of Paris, that some species of them 

 form the principal part of the 

 masses of stone in some of the 

 quarries. The remains of such 

 minute animals as the milliola, 

 have added much more to the mass 

 of materials forming the earth's 

 crust than the bones of the mam- 

 moths, whales, and hippopotami. 



MI'LLSTONE. Called also Burrhstone. 

 The Quartz .agathe molaire of 

 Haiiy; Silex meuliere of Brong- 

 niart. The exterior aspect of this 

 mineral is somewhat peculiar, being 

 full of pores and cavities, which 

 give it a corroded and cellular 

 appearance. It occurs in amor- 

 phous masses, above the marine 

 sand and sandstone. Sometimes 

 the mass is comparatively compact, 

 and the cavities small and not 

 numerous; but in all specimens 

 these cavities or cells are to be 

 found. Millstone is of a white or 

 greyish colour; sometimes with a 

 tinge of blue or yellow ; when 

 unmixed it is pure silex. It con- 

 tains no organic remains, and in the 

 order of superposition of the for- 

 mations in the neighbourhood of 

 Paris, it constitutes the ninth hor- 

 izontal bed, counting from the chalk 

 upwards. It is of great use for 

 making into millstones,, from which 

 circumstance it has obtained its 

 name. 



MI'LLSTONE GRIT. The name given to 



a silicious conglomerate, composed 

 of the detritus of primary rocks. 

 It has been thus named from some 

 of the strata having been worked 

 for millstones. It constitutes one 

 of the members of the carboniferous, 

 or mountain limestone group. The 

 millstone grit forms a bed of con- 

 siderable thickness in some situa- 

 tions, amounting to three or four 

 hundred feet; in others, it is of 

 very limited extent; and sometimes 

 it is wholly wanting. The mill- 

 stone grit is most commonly seen 

 under the form of a coarse-grained 

 sandstone, consisting of quartzose 

 particles of various sizes, (often 

 sufficiently large to give the rock 

 the character of a pudding-stone,) 

 agglutinated by an argillaceous 

 cement. This sandstone differs 

 from those which accompany the 

 coal measures, principally by its 

 greater induration. It sometimes 

 assumes a finer texture, in which 

 the mechanical structure becomes 

 less evident, and even passes into 

 a hard and solid cherty rock. 



MI'LOSCHINE. The name given to a 

 hydrated silicate of alumina. 



MIMOSI'TES. The name given to fossil 

 fruits belonging to the natural order 

 Mimosese. 



MINERAL ADIPOCI'RE. A fatty bitu- 

 minous substance occurring in the 

 argillaceous iron ore of Merthyr, 

 in Wales. It is insoluble in water, 

 and fuses at a temperature of 160. 

 When cold, it is inodorous; but on 

 being heated, gives out a bituminous 

 odour. 



MI'NEHAL CAOU'TCHOUC. A variety of 

 bitumen, intermediate between the 

 harder and softer kinds. It some- 

 times much resembles India rubber 

 in its softness and elasticity, from 

 whence it derives its name, and, 

 like that, removes the traces of the 

 pencil, but, at the same time, it 

 soils slightly the paper. Colour 

 brown, reddish-brown, or hyacinth- 

 red. Specific gravity from 0.90 to 



