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V A L 



ternary. They are supposed to be 

 of more recent origin than any of 

 the strata composing the formations 

 of the London and Paris basins. 



U'KANITE. An ore of Uranium of a 

 black or green colour, called also 

 Pechblende. 



URA'NIUM. A metallic substance of a 

 grey colour, obtained with great 

 difficulty from a mineral called 

 pechblende. It is infusible. Spe- 

 cific gravity 9'0 to 9 "50. It is 

 found in Saxony and in Cornwall. 

 It imparts a deep orange colour to 

 the enamel of porcelain. 



UECE'OLATE. (from urceolus, Lat. a 

 water-pitcher.) 



1. In conchology, a term applied 

 to a shell that swells in the middle, 

 and is therefore supposed to bear a 



resemblance to a water-pitcher. 

 2. In botany, applied to a calyx or 

 corolla swelling out like a pitcher. 



U'BCHIN. The hedgehog. The name 

 of sea-urchin has been given to the 

 echinus. 



U'TBICLE. (utriculus, Lat. a little 

 bottle.) In botany, a term applied 

 to a species of capsule resembling a 

 small bladder, or a capsule of one 

 cell, which never opens by valves, 

 and drops with the seed. It is 

 thin and transparent, and is more 

 frequently considered to be the 

 external coat of the seed than a 

 real capsule. 



UTEI'CTJLAR. Resembling a utricle in 

 form or shape. The pelvis of 

 apiocrinites is of a tumid utricular 

 form. 



YA'GTNATED. (from vagina, a sheath, 

 Lat.) A term used in botany, 

 sheathed. 



VAGINOPE'NNOUS. (from vagina, a 

 sheath, and penna, a wing, Lat.) 

 Sheath-winged ; having the wings 

 covered with hard cases. 



VAGI'NTTLA. A genus of minute pyra- 

 midal shells, known only as fossils, 

 and found in the tertiary strata 

 near Bordeaux. 



VAI/LEY OF ELE'VATION. This name 

 is given by geologists to a valley 

 which seems to have originated in 

 a fracture of the strata, and a 

 movement of the fractured part 

 upwards, so that the strata dip 

 from the valley on either side. 

 Probably a very large proportion 

 of mountain valleys might be ar- 

 ranged under this head; but, at 

 present, geologists seem to have 

 confined the application of the term 

 to those which are bounded by hills 

 of moderate height. 



VAI/LEY OF DENUD'ATION. A name 

 given by geologists to any valley 

 where the strata are not far re- 

 moved from the horizontal position 

 on either side, and of which the 

 former continuity cannot be 

 doubted. 



VALVA'TA. A genus of small fresh- 

 water univalves belonging to the 

 family Peristomata. Yalvatae are 

 found both recent and fossil. 



YALVE. (valva, Lat. valve, Pr. valva, 

 It.) 



1. In conchology, the shell. When 

 the whole shell of the animal is in 

 one piece, it is called a univalve ; 

 when there are two shells, or the 

 shelly covering consists of two 

 pieces, as in the oyster, muscle, 

 &c., they are called bivalves; and 

 when the covering consists of more 

 than two pieces, multivalves. 



2. In anatomy, a folding door or 

 lid attached to a hollow vessel by 

 means of a hinge, which allows the 



