L I B 



C H5 ] 



L I L 



kind of limestone, which, with its asso- 

 ciated beds, form a particular group of 

 the secondary series. Mr. Bakewell con- 

 siders that the name lias was probably 

 given to this formation by the provincial 

 pronunciation of the word layers, as the 

 strata of lias limestone are generally very 

 regular and flat, and can easily be raised 

 in slabs from the quarry. " The great 

 bed of dark argillaceous limestone, di- 

 vided into thin strata, called lias, is the 

 best characterized of all the secondary 

 strata, (except chalk) both by its mineral 

 characters and the fossil remains im- 

 bedded in it. The lias cannot be mis- 

 taken for any of the lower strata ; it 

 serves as a key to the geology of the 

 secondary formations in England ; and 

 the first enquiry which the student should 

 make, when he is in doubt respecting the 

 position of any of the secondary beds, 

 should be, does it occur above or below 

 the lias ? 



When the lias beds are fully developed 

 with their associated beds of clay, they 

 form a mass of stratified limestone and 

 clay, several hundred feet in thickness, 

 which rests upon the red marl. Bakewell 

 Introd. to Geology. 



The lias group is placed below the 

 oolite, and above the variegated sandstone, 

 in this country ; in France and Germany, 

 below the oolite and above the Muschel- 

 kalk. The Muschelkalk has not been 

 discovered hitherto in England. It is in 

 the lias that the petrified ink-bags of 

 Loligo have been found. Proofs are not 

 wanting of intervals between the depo- 

 sitions of the component strata of the 

 lias. Twenty different kinds of ammo- 

 nites have been discovered in the lias. 

 Gryphites are so abundant in it, that in 

 France it has obtained the name of Cal- 

 caire a Gryphites ; and, indeed, the Gry- 

 phite appears peculiar to, and character- 

 istic of, the lias formation. 



LI'BER. In botany, a layer on the inner 

 surface, or that which is contiguous to 

 the wood, or the bark of trees ; the 

 innermost layer of the bark. The liber 

 appears to be formed from the cambium. 



LI'GAMENT. (ligamentum, Lat. ligament, 

 Fr. ligamento, It.) A strong, flexible, 

 tough, compact, membrane, serving to 

 keep together certain parts. 



" Nothing," says Dr. Roget, " can be 

 more artificially contrived than the inter- 

 weaving of the fibres of ligaments ; for 

 they are not only disposed, as in a rope, 

 in bundles placed side by side, and appa- 

 rently parallel, to each other ; but, on 

 careful examination, they are found to be 

 tied together by oblique fibres curiously 

 interlaced in a way that no art can imi- 

 tate. It is only after long maceration in 



water, that this complicated and beautiful 

 structure can be unravelled." 



In conchology, the membranaceous 

 substance which connects the valves 

 together ; the true ligament is always 

 external. 



LIGAME'NTAL. ) Composed of ligament ; 



LIGAME'NTOUS. $ resembling ligament. 



LI'GNEOUS. (ligneus, Lat. ligneux, Fr. 

 lianeo, It.) Made of wood; resembling 

 wood ; containing wood. 



LIGNI'FEROUS. (from lignum, wood, and 

 fero, to produce, Lat.) Producing wood ; 

 yielding wood. 



LIGNIFICA'TION. The process of being 

 converted into wood. 



LI'GNIN. ^ From an analysis of lignin by 



LI'GNINE. \ Dr. Prout it is found to con- 

 sist of equal parts of water and carbon. 

 Lignin is deposited, during the growth of 

 the plant, with the intention of forming a 

 permanent part of the vegetable structure 

 constituting the basis of the woody fibre, 

 and giving mechanical support and 

 strength to the whole fabric of the plant. 



LIGNIPE'RDOUS. (from lignum, wood, and 

 perdo, to destroy, Lat.) A term applied 

 to insects which destroy wood. 



LI'GNITE. (from lignum, Lat.) Wood- 

 coal. Lignite is brown or black. Some 

 lignite has the appearance of jet, is of a 

 velvet-black, does not soil the fingers, is 

 very brittle, and burns with a bright 

 flame. Lignite is a much more recent 

 formation than that of common coal. By 

 some, lignite is considered to be an im- 

 perfect coal, as wood not yet mineralized, 

 or passed into a state of coal ; while 

 others doubt whether lignite ever becomes 

 true coal. Lignite, like coal, is of vege- 

 table origin, but it differs in many re- 

 spects from common coal. There are several 

 varieties of lignite; these mostly burn 

 with flame, but they neither swell nor 

 cake like coal. 



LIGNI'TIC. Containing lignite ; resembling 

 lignite. 



LI'GULATE. > (from ligula, a strap, Lat.) 



LI'GTJLATED. ] Strap-shaped. A term 

 applied to the radical florets of compound 

 flowers, when shaped like a strap or rib- 

 bon. The projecting parts of the limb of 

 an irregular corolla are called lips ; when 

 one lip is very long and narrow, compared 

 to the length of the tube, the corolla is 

 called ligulate, or strap-shaped. 



LI'GURITE. (from liguria,} A mineral 

 of an apple-green colour, occasionally 

 speckled. It ranks as a gem. 



LI'LALITE. Another name for the mineral 

 lepidolite, which see. 



LILIA'CEOUS. (liliaceus, Lat.) Resem- 

 bling a lily ; lily-like. A corolla having 

 six regular petals is termed a liliaceous 

 corolla. 



