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we have ossiferous gravel, ossiferous 

 clay, ossiferous strata, ossiferous 

 caves, &c., &c. 



OSTEOCO'LLA. (from cxneov, a bone, 

 and Ko\\a, glue, Or.) Vegetables 

 of the most delicate texture, when 

 immersed in waters containing car- 

 bonate of lime, become incrusted, 

 still preserving their form even to 

 their most delicate ramifications. 

 These incrustations somewhat re- 

 semble the bone of an animal, and 

 the property has been absurdly at- 

 tributed to them of facilitating the 

 union of fractured bones. 



OSTEOLE'PIS. (from osreoi/, a bone, 

 and XeTrts, a scale, Gr.) The name 

 assigned by Mr. Pentland and M. 

 Valenciennes to a genus of fossil 

 fishes, found in the old red sand- 

 stone of Scotland. Six species 

 have been described. Sir R. Mur~ 

 chison states that this genus has 

 not hitherto been discovered in the 

 old red sandstone of England. The 

 osteolepis had a shell as naked as 

 its teeth, the bone being merely 

 covered by a hard shining enamel ; 

 its toes also were of bare enamelled 

 bone. The enamelled teeth were 

 placed in jaws which presented 

 outside a surface as naked and as 

 finely enamelled as their own. The 

 entire head was covered with enam- 

 elled osseous plates, furnished in- 

 side, like other bones, with their 

 nourishing blood vessels. The fins 

 had a sort of bird-wing construction. 

 The mouth opened below the snout, 

 but not so far below it as in the 

 purely cartillaginous fishes. It was 

 thickly furnished with slender and 

 sharply-pointed teeth. The gills 

 opened, as in the osseous fishes, in 

 continuous lines, and were covered 

 by large bony opercules. "While 

 the head and its appendages re- 

 sembled, in some points, the bony 

 fishes, the tail differed in no respects 

 from the tails of cartilaginous ones. 

 In size, the osteolepis varied from 

 six to twelve inches. 



OSTEO'LOGY. (from ooreoi/, a bone, 

 and Xo'709, discourse, Gr.) A des- 

 cription of the bones ; that part of 

 anatomy which treats of the bones. 

 That branch of science named fossil 

 osteology has assumed a most im- 

 portant character, for which we are 

 mainly indebted to the labours of 

 Cuvier. From a single fragment 

 of a bone, certainly of a character- 

 istic part, the order and genus of 

 the animal may be determined with 

 a precision amounting almost to 

 mathematical certainty. 



OSTEO'LOGICAL (from Osteology.) 



OS'TRACITE. A fossil oyster. 



OSTRA'CODA. The fifth order of the 

 class Crustacea, comprising Cypris 

 and Cythere. 



OSTRJS'A. j The oyster. A rough, 



OS'TREA. ) adherent, inequivalved 

 bivalve ; the hinge without a tooth. 

 One muscular impression in each 

 valve. The oyster is found both 

 fossil and recent. Of this genus, 

 one hundred and thirty-seven spe- 

 cies have been described in Turton's 

 Linne. The most extraordinary 

 shell of this genus for size, says 

 Mr. Parkinson, is the large fossil 

 oyster, the recent analogue of which, 

 from Virginia, appears to be de- 

 picted by Lister. Some attain to 

 the length of twenty inches. An 

 under valve in Mr. Parkinson's 

 possession weighed four pounds, 

 being thirteen inches in length and 

 three in thickness. 



OUTCROP. A term, used by miners, to 

 express the exposure at the surface 

 of a stratum or strata. 



OU'TLIEK. A portion of a stratum 

 detached from the principal mass, 

 and lying detached at some distance 

 from it. 



O'VA ANGTJI'NA. A species of fossil 

 cidaris or echinus. 



O'VAL. (from ovum, an egg, Lat, ovafo, 

 Fr. ovdle. It.) A rounded surface, 

 its two right-angular diameters be- 

 ing of an unequal length, so that 

 its longest transverse diameter does 



