Notes on the Geology of Hassanein Bey’s Expedition, Sollum-Darfur, 1923
F. W. Moon
HAVING been requested by Hassanein Bey, in the absence of Dr. Hume, to report upon the interesting geological specimens collected by him on his recent exploratory tour through the Western Desert from Sollum, on the southern shores of the Mediterranean Sea, to Darfur in the Sudan, I have much pleasure in submitting the following short summary of the main features of the journey from a geological point of view, as deduced from the specimens collected.
Although the specimens are small and, in the case of the igneous rocks, much weathered, yet for all intents and purposes they are quite sufficient to enable one to make deductions and conclusions as to the main geological formations passed over.
As the explorer explains, there was not the freedom of transport he would have desired for making a larger collection of full-sized specimens, nor did he wish to incur the displeasure of those who formed his escort by seeming to do anything that might appear in any way suspicious, such as the constant breaking and collecting of stones.
From the tabulated list of specimens herewith appended, it may be seen that the beginning of the journey was made over Miocene formations indicated by fossil oysters and pectens (identified as Ostrea digitalina, O. Virleti, Chlamys zitteli, and others), of which there are seven valves of the former, two of the second, two of the third, and five which resemble Chlamys sub-malvinæ.
The Miocene formations continue through Siwa, Jaghbub, and Jalo, and far southward to a point about 180 km. to the south of Jalo (see Specimens 1-4), where the last Miocene specimen (No. 4) was picked up.
At this point begins a wide barren stretch of flat and desolate country, devoid of rocks of any particular geological interest beyond the thin covering of “sand and alluvium” which extends for nearly 200 km. (four days of monotonous marching) along the route to the south.
Then, when about 50 km. north of Zieghen, the explorer noticed that the aspect of the country took a sudden change; the light yellow of the Miocene limestones and desert sands gave place to brighter, more varied, and highly colored scenery, which the specimens show was due to the approach of the Lower Cretaceous Nubian Sandstones, which, wherever they occur, add beauty to the landscape in unbelievable brilliancy and variety of coloring.
Although greens and blues are sometimes observed, red is the dominant color, all shades of pink, terra-cotta, maroon, and brick red are blended together, and umbers and ochers are sometimes present.