620 
APPENDIX. 
[C. 
The cementing lime-stone in the rock of this island, is 
very like some of the more compact portions of the stone 
of Guadaloupe, which contains the human skeletons, the 
hardness and fracture being nearly the same in both. The 
chief difference of these rocks seems to arise from the na- 
ture of the cemented substances; — which, in the Guada- 
loupe stone, being themselves calcareous, are incorporated, 
or melted as it were, into the cement, by insensible gra- 
dation* ; while the quartzose sand, in that of Dirk Hartog’s 
Island, is strongly contrasted with the calcareous matter 
that surrounds itf. But, wherever the imbedded fragments 
in the latter consist of lime-stone, their union with the 
cement is complete. 
Rottnest Island, about four hundred and fifty miles 
south of Dirk Hartog’s Island. — Indistinct specimens con- 
taining numerous fragments of shells, in a calcareous ce- 
ment; the substance of these shells has at first sight the 
et se composent d’un grand nombre de zones concentriques, qui se 
developpent autour d’un noyau central d’un gres scintillant et 
brunatre. Ces diverses couches ont a peine quelques raillimitres 
d’epaisseur, et affectent des nuances agreables, qui varient depuis 
le rouge-fonce jusqu'au jaune-clair. La disposition generale de 
cette breche lui donne done quelques rapports grossiers avec le 
granit globuleux de Tile de Corse ; et, par ses couches rubanees, 
concentriques, elle a quelque chose de I’aspect des Agathes-Onyx. 
Les bancs de gres divers dont je viens de parler, consti- 
tuent, a bien dire, la masse entiere du pays qui nous occupe, &c.” — 
Vol. 1. p. 110. See also Freycinet, p. 187. 
* See Mr. Koenig’s Paper. Phil. Trans, vol. civ. (1814) p. 107, 
&c. 
t Captain King informs me that the soundings in this part of 
the coast, bring up a very fine quartzose- sand, like that cemented in 
the breccia. 
