CRETACEOUS FORMATIONS. 09 



detached and fragmentary condition in which the part of the skeletons of these huge 

 winged reptiles have reached us, we are reduced in the attempts at their restoration. 



In a mass of white chalk, about thirteen inches in length, in the collection of Thomas 

 Charles, Esq., are imbedded three portions of long-bones ; one of these (T. XXIV, 

 fig. 1,) is seven inches in length, and shows a crushed articular extremity, 2 inches 

 2 lines in diameter, the shaft at the opposite fractured extremity being 1 inch 3 lines in 

 the longest diameter ; a second fragment (T. XXIV, fig. 3,) is 6^ inches in length, with 

 a diameter of 8 lines at its smaller fractured end, and a diameter of 1 inch 3 lines at its 

 larger fractured end, to which it gradually expands ; the third portion (fig. \, a a,) may 

 be a part of the same bone, as fig. 3 ; it extends from close to the smaller fractured end 

 of that bone in the opposite direction, but in the same line, gradually expanding ; its 

 length being 5 inches, and its diameter at the broader fractured end about one inch. 



The largest portion of bone (T. XXIV, fig. 1,) presents at its expanded end two 

 surfaces, divided by a strong ridge, about one inch in length, the prominent summit 

 of which has been broken away. One of the surfaces is three times the breadth 

 of the other and is slightly concave transversely, becoming flat as it recedes from 

 the ridge to the tuberosity which terminates the end of the bone furthest from 

 the ridge. This tuberosity is subcompressed ; many linear impressions, indicative of 

 the insertion of an aponeurosis or ligament, radiate from it upon the flat surface of 

 the bone : a slight concavity on the end of the bone bounds the tuberosity opposite 

 to the ridge ; the rest of that end, including the articular surface, is, as usual, 

 destroyed. The second surface is flat, and slopes away at an open angle from the 

 broader one. Below these surfaces, the outer layer of the thin, compact, osseous 

 wall, has scaled off, and the shaft has been fractured across obliquely, about three 

 inches from the expanded end. The thin wall of the shaft is then continued in broken 

 portions for about three inches lower down, and the rest of the shaft is represented by 

 the cast of its interior in the white chalk. This cast shows, on the surface which was 

 next the bone, several impressions, chiefly in an oblique direction, and nearly parallel 

 with one another ; they are shallow and smoothly rounded at the bottom, and may be 

 presumed to have been left by ridges on the inner surface of the medullary or pneu- 

 matic cavity of the bone : blood-vessels merely would have perished before the chalk, 

 which must have been introduced into the cavities of these bones in a soft state, 

 could have hardened sufficiently to retain the impression. 



With regard to the two other fragments, which are probably parts of an anti- 

 brachial bone of the same wing, there is even less character to be obtained from an 

 articular end than in the preceding fragment. On the supposition that the two 

 portions belong to the same bone, it must have been upwards of fourteen inches in 

 length. In the portion, T. XXIV, fig. 3, a part of the inner surface of the thin 

 compact wall of the medullary cavity of the bone is exposed : its smoothness is broken 

 by feeble linear elevations, which are reticularly disposed : it is in appearance very 



