436 EGYPT 
however, Mr. Arrow says that the species is not represented at South 
Kensington. 
Orthoptera were less common than might have been expected, 
but Truxalis nasuta , Linn., was among the denizens of the desert. 
One afternoon, when walking near the Third Pyramid with an un¬ 
scientific acquaintance, he followed my example by turning over a 
stone, and forthwith, in accordance with the well-known law 
regulating such matters, unearthed something that I had myself 
not come across even in turning many stones, viz. two Cockroaches, 
Polyphaga africana , Linn., which (when alive) were of a pale sandy 
colour. A few minutes later this gentleman’s wife called Mrs. Long- 
staffs attention to something running very swiftly in a straight line 
over the smooth sand. Greatly to our friends’ amusement my wife 
pursued the creature at high speed, ultimately effecting its capture. 
It turned out to be the Mantid, Eremiaphila hmlili, Lefebvre, new 
to the Hope Collection. During the whole of my time in Egypt I 
had been, at Mr. W. F. Kirby’s special request, on the look-out for 
examples of that little-known genus. Apart from its swiftness of foot, 
the insect is almost white when alive and in the highest degree cryptic. 
A good many fossils might easily be obtained in the Cairo 
district. The Mukattam Hills above the Citadel are of Eocene lime¬ 
stone, full of fossils, and, as is well known, Kummulites may be 
picked up off the sand at the foot of the Great Pyramid (which is 
indeed to a great extent built of those Foraminifera), while a couple 
of miles to the south a valley cutting into the escarpment exposes 
Miocene beds that are extremely rich in fossil remains. Amongst these 
are numerous large, somewhat flattened Echinids, Glypeaster aegypti- 
acus, Mich., which may be found on the surface, weathered-out, and 
in a remarkable state of preservation. One day I rode a dozen miles 
to the westward to Gebel Dixon, at the foot of which is an extensive 
“ petrified forest,” said to have been discovered by my kinsman, Mr. 
Waynman Dixon, civil engineer and Egyptologist; at any rate, it 
would appear that he first brought it to notice. I do not happen to 
have come across any explanation of these “petrified forests.” The 
general appearance is that of a wood which had been destroyed by 
fire—the only remains being an accumulation of trunks and 
branches lying on the surface fully exposed. This exposure I take 
to be the result of sub-aerial denudation. The blowing sand has, by 
attrition, disintegrated all softer material which has been removed by 
the wind, leaving behind the hard silicified wood as we see it to-day. 
There is plenty of evidence in the desert of the power of blowing 
sand to effect such a work. 
