§42. OSSEOUS BRECCIA, OR BONE-CONGLOMERATE. 185 



other extinct species, human bones, fragments of pottery, 

 terrestrial shells, and bones of animals of modern times, 

 may therefore be associated.* Such are the contents of 

 numerous caves, and this explanation shows how they may 

 have been accumulated, f 



42. Osseous breccia, or bone-conglomerate. — The 

 facts we shall next examine are even more extraordinary 

 than those already described ; for the fossil remains are not 

 imbedded in gravel or clay, or collected together in caves, 

 but occur in fissures of limestone, over an area of many 

 hundred leagues, and in rocks and islands very remote 

 from each other. The limestone presents but little variety, 

 the substance in which the fossils are enveloped is every- 

 where the same, and the bones belong, with few exceptions, 

 to similar species of animals. The rocks in which they 

 occur have been shattered in every direction, and the 

 fissures are filled, more or less completely, with what geolo- 

 gists term an osseous or bone-breccia ; that is, an aggrega- 

 tion of bones held together by a calcareous cement or paste, 

 in the same manner as the conglomerated shingle near 

 Brighton (p. 79) ; or, to exemplify its nature by a still 

 more familiar illustration, the mixture of mortar, pebbles, 

 &c. which is employed in masonry, and called concrete. 



This cement is of a reddish brown colour, and much 

 resembles common brick, while the bones are beautifully 

 white, and in many instances have their cavities lined with 

 spar. In some examples the bones have undergone but 

 . little change ; in others, the cells of the cancellated structure 

 are filled with calcareous matter. The specimen before us 



* Memoir by M. Desnoyer. 



f The femur of the Bear is so like the human thigh-bone, as to 

 be readily mistaken, without due caution; see Trof. Owen; British 

 Mammalia, p. 96 : in which the distinctive characters of each are 

 pointed out. 



