422 
TRAVELS IN AFRICA. Chap. LXXXV. 
by this rocky chain, and towards the west at the dis- 
tance of about three miles, as well as towards the 
north by sandy downs. The higher level itself, over 
Hvhich our track lay, was broken by considerable de- 
pressions, running east and west, and forming such 
steep slopes, that Clapperton's expression of high 
sand hills, which he had here to cross seems well 
justified ; and we ourselves took up our encampment 
after a march of a little more than eleven miles in a 
hollow of this description, bordered by high sand 
hills towards the west. However, our halt was very 
short, and soon after midnight we pursued our march, 
the desert now becoming more level, and therefore 
allowing a steady progress by night. Pursuing our 
march with alacrity, we encamped after a stretch of 
about sixteen miles in a spot which was full of those 
remarkable crystallized tubes which are called " bar- 
gom-chidibe," by the Kaniiri, and " kauchin-kassa," 
by the Hausa people ; and the character of which 
has been explained in such various ways, some sup- 
posing them to be the effect of lightning, while others 
fancy them to be the covered walks with which the 
white ant had surrounded stalks of negro corn. Pur- 
suing from here our march, a little before two in the 
afternoon we entered a sandy waste, which well de- 
served to be compared to the wide expanse of the 
ocean, although even here small rocky ridges pro- 
truded in some places ; and after a march of about ten 
miles, we ourselves encamped under the protection of 
such a ridge. 
