250 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
PLATE 30. 
Map 3.—Sketch-map of Salak and the Barrier reefs extending from its point. 
Soundings with line and dot above mean that so many fathoms of line were 
run out without reaching the bottom. Small crosses indicate presence of dangerous 
rock. 
PLATE 31, 
Marv 4.—Jedda Reefs. 
The reefs round Jedda illustrate the parallelism of the structures of either side 
of the Red Sea, and are a case of this effect influencing features. of a very small 
scale equally with such larger things as hill-ranges. 
Surface-reefs are shaded. Shore and islands dotted. 
S=fathonalinney pulse Mepieaee sya herve eee 
10-fathom line —:—.—.+— 
t will be noticed that the 5- and 10-fathom lines are frequently coincident. 
Three miles west of the outermost reef of this chart the plateau shoals from 30 
to 15 and 10 fathoms and bears several shoals. This area is closely skirted by the 
100-fathom line, and 200 fathoms is found ; mile further west. 
PLATE 32. 
THREE VIEWS ON RAwayYa. 
1. Entrance to Khor Atof; notice the river-like appearance of this inlet, and 
the very low land surrounding it. The dark line along the horizon, here only half 
a mile away, is the land on the other side of the Khor, and shows how low-lying 
is the greater part of Rawaya (cf. fig. 2). Foreground is composed of sections of 
coral and shells of an elevated reef; the actual shore is sandy and bears a little 
vegetation, that included in the photograph being Salicornia fruticosa. 
2. The Salt Field, Jebel Abu Shagara beyond it. 
8. The ravine of Jebel Abu Shagara, showing :— 
(1) A shallow layer of coral ; 
(2) Six feet of gypsum ; 
(8) Sandstone, containing glassy sheets of selenite, recrystallised from the 
gypsum. 
PLATE 33. 
Fies. 1 & 2. Corals in position of growth on the summit of Jebel Tétawib. Notice their 
perfect preservation. 
3. An example of the undermined cliffs of the Red Sea Coast. These are on the west 
side of Rawaya. Note how the same undermining is beginning on the fallen 
blocks in the foreground. 
PLATE 34. 
Looking across Dongonab Harbour in a southerly direction, 7.e. from directly 
behind the sand hillocks. In the foreground is the most recent and not yet 
perfectly consolidated part of the sand plain, and the line of Swaeda and sand 
hillocks which bounds it seawards. Across the bay is the native village on the 
same low-lying sand, the rising ground to the right being Dongonab Hill, of — 
the older gravelly alluyium. 
