LAG 



[ 138 ] 



LAM 



the land. "If we drain a lake," says 

 Mr. Lyell, u we frequently find at the 

 bottom a series of deposits, disposed with 

 great regularity one above the other ; the 

 uppermost, perhaps, may be a stratum of 

 peat, next below a more compact variety 

 of the same, still lower a bed of lami- 

 nated marl, alternating with peat, and 

 then other beds of marl, alternating with 

 clay. Now if we sink a second pit 

 through the same continuous lacustrine 

 deposit, at some distance from the first, 

 we commonly meet with nearly the same 

 series of beds, yet with slight variations ; 

 some, for example, of the layers of sand, 

 clay, or marl may be wanting, one or 

 more of them having thinned out, and 

 given place to others, or sometimes one 

 of the masses, first examined, is observed 

 to increase in thickness to the exclusion 

 of other beds. At length we arrive at a 

 point where the whole assemblage of la- 

 custrine strata terminate, as, for example, 

 when we arrive at the borders of the 

 original lake-basin." Prof. J. Philips 

 observes, "lacustrine deposits of un- 

 doubtedly meiocene age are scarcely 

 known. On the coasts of Yorkshire and 

 Lancashire, lacustrine deposits occur at 

 many points, and present a considerable 

 variety of circumstances as to level, above 

 or below the sea, sandy, marly, or peaty 

 composition ; but are always governed by 

 the general condition, that they occupy 

 small hollows on the surface of the diluvial 

 accumulations . 



LAGA'NUM. A fossil echinite thus named 

 by Klein, called also pancake. 



LAGO'MYS. (from Xdyoc, a hare, and 

 fivg, a rat, Gr.) A rat hare. A genus of 

 animals forming a link between the hare 

 and the rat. The lagomys is placed by 

 Cuvier in the order rodentia. They have 

 been found in Siberia only, and are de- 

 scribed by Pallas. There are several 

 species ; One has been found fossil in the 

 osseous breccia of Corsica. The lagomys 

 has ears of a moderate size ; legs nearly 

 alike ; clavicles almost perfect ; and no 

 tail. The Rev. W. Kirby observes of the 

 lagomys, "it ought rather to have been 

 called the hay-maker, since man may, or 

 might, have learned that part of the busi- 

 ness of the agriculturist, which consists 

 in providing a store of winter provender 

 for his cattle, from this industrious ani- 

 mal. The Tungusians, who inhabit the 

 country beyond the lake of Baikal, call it 

 Pika, which has been adopted as its 

 trivial name. These animals make their 

 abode between the rocks, and during the 

 summer employ themselves in making hay 

 for a winter store. About the middle of 

 August these little animals collect with 

 admirable precaution their winter's pro- 



vender, which is formed of the choicest 

 grasses and the sweetest herbs, which 

 they bring near their habitations and 

 spread out to dry like hay. In Septem- 

 ber, they form heaps or stacks of the 

 fodder they have collected under the rocks, 

 or in other places sheltered from the rain 

 or snow. Where many of them have 

 laboured together, their stacks are some- 

 times as high as a man, and more than 

 eight feet in diameter. A subterranean 

 gallery leads from the burrow, below the 

 mass of hay, so that neither frost nor 

 snow can intercept their communication 

 with it. Bridgewater Treatise. 



LAGOO'N. } (laguna, It.) A salt-water 



LAGU'NE. \ lake. 



LAKE. (lacus, Lat. lache, Germ, lac or 

 laque, Fr. lago, It.) A large collection of 

 inland water. Some of the lakes of 

 America are upwards of 1500 miles in 

 circuit. The filling up of lakes, and the 

 formation of deltas at their mouths, form 

 subjects of great importance to the geo- 

 logical student. In lakes, the diminu- 

 tion of the surface, by the gradual in- 

 crease of land at the mouths of rivers 

 which flow into them, is remarkable. The 

 mud and debris brought by the Rhone 

 into the lake of Geneva, and deposited near 

 its entrance, has caused an advance of the 

 land to the extent of two miles within 

 1700 years, the Roman harbour Portus 

 Valesise, now called Port Vallais, being 

 at this time two miles distant from the 

 lake. 



LAMA'NTIN. ) The manatus of Cuvier. A 



LAMA'NTINE. $ species of herbivorous 

 cetacea, living upon the plants which 

 grow at the bottom of the sea. The 

 lamantin appears to have existed during 

 the miocene and pliocene periods. Fossil 

 remains have been discovered in France. 

 The existing species of the lamantine are 

 found near the mouths of rivers in the 

 hottest parts of the Atlantic ocean and in 

 the torrid zone, and the discovery of their 

 fossil remains in Europe adds another 

 link to the long chain of evidence of a 

 diminished temperature of the climate of 

 Europe. 



LAMBDOI'DAL. (from the Greek letter 

 XctfiSa, and dSos, form.) The name 

 given to one of the sutures of the cra- 

 nium, from its supposed resemblance in 

 form to the Greek letter A. 



LAME'LLA. (lamella, Lat.) A thin plate 

 or scale. This word is generally used in 

 the plural, lamellae. 



LA'MELLATED. Composed of thin plates, 

 layers, or scales. In conchology, when a 

 shell is divided into thin and distinct 

 plates or layers, overlying each other with 

 the edges produced. 



LAME'LLAR. Composed of minute plates 



