M U L 



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M Y A 



MU'LTIVALVE. (from multus, many, ' 

 and valvce, valves, Lat.) Some of 

 the mollusca have, in addition to 

 the two principal valves, small 

 supplementary pieces of shell ; 

 these have been comprised in the 

 order of multivalves. 



MU'NDIC. Iron or arsenical pyrites, 

 which strike fire with amazing 

 facility. The term, says Dr. Paris, 

 seems to be derived from this 

 quality. 



MT/RCHISONIA. A genus of fossils of 

 the Silurian formation. 



MU'RCHTSONITE. A mineral, thus named 

 by Mr. Levi, in honour of Sir R. 

 ' Murchison. Its constituents are 

 silica 68*10, alumina 16*6, potash 

 14-8. It occurs near Dawlish ; it 

 is a variety of felspar. 



MtfREX. (murex, Lat. murex, Pr.) 

 A genus of shells. Animal a 

 limax: shell univalve, spiral, rough, 

 with membraneous sutures ; aper- 

 ture oval, ending in an entire 

 straight, or slightly ascending 

 canal. The murex is an inhabitant 

 of the ocean, found at depths 

 varying from five to twenty-five 

 fathoms, on different bottoms. 

 These shells, besides their long chan- 

 nelled beaks, are remarkable for the 

 beauty and variety of their spines. 

 Murices, or rock-shells, were in high 

 esteem from the earliest ages, on 

 account of the dye that some of 

 them yielded ; cloths dyed with it 

 bearing a higher price than others. 

 More than one species yielded a 

 dye; one, according to Bochart, a 

 glaucous or azure colour ; the 

 other, a purple. Different species 

 of fossil murex are found in the 

 London clay andintheBognor sand- 

 stone, and Lamarck describes many 

 species found in the neighbourhood 

 of Paris. 



MTJ'REX CONTRA'RIUS. The reversed 

 whelk, now more commonly known 

 as Fusus contrarius, is a sinistral 

 shell, and is found most abundantly 



in the crag formation, of which it 

 appears characteristic. 



MTfRiAdTE. A name given to anhy- 

 drite, by Klaproth. See Anhy- 

 drite. 



MTT'BICA.TED. (murwatus,~Lat.) Clothed 

 with sharp rigid points ; beset with 

 short erect spines. 



MTJ'RICITE. The fossil murex. 



MFSA'CEA. A family of tropical mon- 

 ocotyledonous plants, including the 

 banana and plaintains. 



MT/SCLE BAND. The name given to a 

 bed of ironstone, found about the 

 middle of the coal series in Derby- 

 shire, and thus named from its 

 containing a very large number of 

 different species of mytili. 



MTJ'SCHEL-KALK. (from muschel, shell, 

 and Icalk, lime or chalk, Germ.) A 

 compact hard limestone, of a grey- 

 ish colour, found in Germany. It 

 belongs to the red sandstone group. 

 The muschel- kalk of Germany 

 cannot be considered to have any 

 precise equivalent among the Eng- 

 lish strata, and indeed would appear 

 to be unknown in England and the 

 north of Germany. It occasionally 

 is met with of sufficient hardness 

 to be employed as marble. In 

 Bavaria and Wurtemburg the mus- 

 chel-kalk is interposed between the 

 red sandstone, on which it rests, 

 and the variegated marls which lie 

 over it, and with which, at the 

 junction, it alternates. The mus- 

 chel-kalk abounds in organic 

 remains. 



MUSCLE-BIND. The name given to a 

 stratum of imperfect ironstone and 

 indurated shell, found in the 

 Derbyshire and Yorkshire coal 

 fields. 



MU'SITE. | A mineral, thus named 



MtfssiTE. ) from Mussa, in Pied- 

 mont, where it occurs. It is a 

 white, or pale green, variety of 

 augite. 



MY' A. (from fwtav, a muscle, Gr.) 

 A genus of bivalves belonging to 

 the family Myacidse. Animal an 



