150 
APPENDIX. 
to be considered as silicified; and they have been errone¬ 
ously so described in some printed notices on this subject 
in the Calcutta Gazette, March 21st, 1827, and in other 
publications. Such, however, is not the case with any 
specimen I have seen in the whole collection ; the cancelli 
of the bones are filled either with hydrate of iron or car¬ 
bonate of lime, and their weight and strength thereby in¬ 
creased, but no other kind of change or injury to their 
external form has been produced. 
It is, in fact, to the strength and indestructibility result¬ 
ing from the mineral impregnation above-mentioned, that 
we owe the discovery of these remains on the shores of the 
Ira wadi. An accident that delayed for some days the 
steam-boat in which Mr. Crawfurd was descending this 
river, allowed him to land, accompanied by Dr. Wallich, 
and to investigate the structure of the country for some 
miles on the north-east of Wetmasut. The accident arose 
from the shallowness of the water, when the steam-boat 
was descending, which, fortunately for geology, caused it 
to run aground near the wells of petroleum, where the left 
bank of the river presents a cliff of several miles in length, 
generally perpendicular, and not exceeding eighty feet in 
height. At the bottom of this cliff the strand was dry, and 
on it were found specimens of petrified wood and bones, 
that had probably fallen from the cliff in the course of its 
decay; but no bone was discovered in the cliff itself by 
Mr. Crawfurd and Dr. Wallich ; nor were they more for¬ 
tunate in several places where they dug in search of bones 
in the adjacent district. This district is composed of 
sand-hills that are very sterile, and is intersected by deep 
ravines: among the sand are beds of gravel, often ce¬ 
mented to a breccia by iron or carbonate of lime; and scat¬ 
tered over its surface at distant and irregular intervals. 
