er barriers of rock;
and we are told by Sir Alexander, that though "the mountains here are
generally composed of granite or mica, at _Reg-Rawan_ there is sandstone
and lime." The situation of the sand is curious, he adds: it is seen
from a great distance; and as there is none other in the neighborhood,
"it might almost be imagined, from its appearance, that the hill had
been cut in two, and that the sand had gushed forth as from a sand-bag."
"When set in motion by a body of people who slide down it, a sound is
emitted. On the first trial we distinctly heard two loud hollow sounds,
such as would be given by a large drum;"--"there is an echo in the
place; and the inhabitants have a belief that the sounds are only heard
on Friday, when the saint of _Reg-Rawan_, who is interred hard by,
permits." The phenomenon, like the resembling one in Arabia, seems to
have attracted attention among the inhabitants of the country at an
early period; and the notice of an eastern annalist, the Emperor Baber,
who flourished late in the fifteenth century, and, like Caesar, conquered
and recorded his conquests, still survives. He describes it as the
_Khwaja Reg-Rawan_, "a small hill, in which there is a line of sandy
ground reaching from the top to the bottom," from which there "issues in
the summer season the sound of drums and nagarets." In connection with
the fact that the musical sand of Eigg is composed of a disintegrated
sandstone of the Oolite, it is not quite unworthy of notice that
sandstone and lime enter into the composition of the hill of
_Reg-Rawan_,--that the district in which the hill is situated is not a
sandy one,--and that its slope of sonorous sand seems as if it had
issued from its side. These various circumstances, taken together, lead
to the inference that the sand may have originated in the decomposition
of the rock beneath. It is further noticeable, that the _Jabel Nakous_
is composed of a white friable sandstone, resembling that of the white
friable bed of the Bay of Laig, and that it belongs to nearly the same
geological era. I owe to the kindness of Dr. Wilson of Bombay, two
specimens which he picked up in Arabia Petraea, of spines of Cidarites of
the mace-formed type so common in the Chalk and Oolite, but so rare in
the older formations. Dr. Wilson informs me that they are of frequent
occurrence in the desert of Arabia Petraea, where they are termed by the
Arabs petrified olives; that nummulites are also abundant in