L I A 



[ 256 ] 



L I G 



The upper portion of the deposits 

 constituting the lias, including 

 about two thirds of their total 

 depth, consists of beds of a deep 

 blue marl, containing only a few 

 irregular and rubbly limestone 

 beds. In the lower portion, the 

 limestone bedsincreasein frequency, 

 and assume the peculiar aspect 

 which characterises the lias, pre- 

 senting a series of thin stony beds, 

 separated by narrow argillaceous 

 partings ; so that quarries of this 

 rock at a distance assume a striped 

 and riband-like appearance: in the 

 lower beds of this limestone, the 

 argillaceous partings often become 

 very slight and almost disappear, 

 as may be seen in the lias tract of 

 South Wales: beds of blue marl, 

 with irregular calcareous masses, 

 generally separate these strata from 

 the red marl belonging to the ad- 

 jacent new red-sandstone forma- 

 tion. The blue lias, which contains 

 much iron, affords a strong lime, 

 distinguished by its property of 

 setting under water; the white 

 lias takes a high polish, and may 

 be employed for the purposes of 

 lithography. 



The lias, which may be regarded 

 as the base of the oolitic system, 

 may be traced on the south-west 

 to Lyme Regis, in Dorsetshire, and 

 on the north-east to "Whitby, in 

 Yorkshire. Near the latter place, 

 it is more fully developed than in any 

 other part of the kingdom, and has 

 been divided by Prof. Phillips into 

 three parts. 



The building stone obtained from 

 the lias is, in general, when first 

 taken from the quarry, dressed with 

 great ease, but on exposure to the 

 atmosphere it parts with the moist- 

 ture which it possessed when under- 

 ground, and becomes much harder. 



The lias group is placed below 

 the oolite, and above the variega- 

 ted sandstone, in this country ; in 

 Prance and Germany, below the 



oolite, and above the Muschelkalk. 

 It is in the lias that the petrified 

 ink-bags of Loligo have been found. 

 Proofs are not wanting of intervals 

 between the depositions of the 

 component strata of the lias. Gry- 

 phites are so abundant in it, that 

 in Prance it has obtained the name 

 of Calcaire a Gryphites; and, in- 

 deed, the Gryphite appears peculiar 

 to, and characteristic of, the lias 

 formation. 



LIA'SSIC. Belonging to the lias. The 

 remains of reptiles, those of sau- 

 rian s in particular, are very common 

 in the liassic rocks in certain parts 

 of England. 



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'CHENS. The third order of the 

 class Thalogens, in the vegetable 

 kingdom. 



LIE'VEITE. An earth mineral, called 

 also Yenite ; Lievrite after Le Lie- 

 ore, and Yenite, in commemoration 

 of the battle of Jena. Lievrite is 

 of a brown, or brownish-black co- 

 lour, sometimes dull externally, 

 but the crystals are often brilliant, 

 and opaque ; it scratches glass, but 

 is scratched by adularia. It occurs 

 amorphous, acicular, and also crys- 

 tallized. Analysis, silex 29-278, 

 lime 13-779, alumine 0-614, black 

 oxide of manganese 1'587, water 

 1-268. Specific gravity 3-8. It 

 is found in Elba, and also in Sibe- 

 ria and Norway. 



LI'GAMENT. (ligamentum, Lat. liga- 

 ment, Er. ligamento, It.) A strong, 

 flexible, tough, compact, membrane, 

 serving to keep together certain 

 parts. 



"Nothing," says Dr. Eoget, 

 " can be more artificially contrived 

 than the interweaving of the fibres 

 of ligaments ; for they are not only 

 disposed, as in a rope, in bundles 



