2 CONTENT SOFA BONE CAVE. 



ble relative positions when found. The bones of the Ambtyrhiza inunclata first 

 found were of an earthy-brown color. Those contained in the next sending were, 

 some of them, of a brilliant vermilion color, and not encrusted. Others were of 

 the usual earthy-brown color, and more or less encrusted; others of this lot were 

 of a rusty red and not encrusted. The specimens of AmMyrhiza q-uad raits and 

 A. latidens, subsequently discovered, are of a brownish-red, and are all encrusted 

 with a thin calcareous layer. When this is removed their color is white. The 

 bones of the ruminant and the shell-chisel are of the same superficial color, but 

 were not encrusted. 



As regards the mineral character of the bones, there is nothing to distinguish 

 them from each other. They absorb moisture, so that broken surfaces adhere 

 when brought into contact with the lips. A few specimens which do not display 

 this character are not to be distinguished as to species from those that do. So 

 there is no superficial character by which any distinction of age among these fossils 

 can be made. 



In the following pages the species are described in detail. 



EEPTILIA. 



IGUANA, Linn. 



The femur of a species of this genus was found at the time of the discovery of 

 the Amblyrhiza latidens. In form and character it very closely resembles existing 

 species of the genus. 



The femur, which is that of the left side, has a gentle fore and aft sigmoid 

 flexure. The head is laterally compressed, and is directed upwards and inwards. 

 The trochanter is large, and forms a stout ala whose inferior extremity approaches 

 and then sinks abruptly into the shaft. It is not curved, but its superior angle is 

 thickened. It does not reach to the level of the angular margin which encircles 

 the head. A low swelling marks the place of the little trochanter. The shaft is 

 cylindric. The inferior extremity is transversely expanded, but there are no 

 epicondyles. The condyles are but little contracted at the middle, but the external 

 is much the larger. Its rotular face is entire, while that of the inner condyle has 

 a shallow fossa on its posterior face. They are not separated by a popliteal notch, 

 and have a very shallow trochlear groove anteriorly. There is a popliteal fossa. 

 There is a slight epicondylar tuberosity on the superior external side of each 

 condyle. 



MEASUREMENTS. 



If. 



Totallength . . . . . . . . . .015 



Long diameter of head 



Diameter at apex of great trochanter . . -015 



of shaft .... -007 



, (fore and aft .... .006 



of condylep 



(.transverse , . . 



