ADDRESS. 19 
perennial, streams, as old river terraces were found rising 
several feet above the present beds of the valleys. The 
presence of such terraces is not to be altogether accounted 
for from the occurrence of occasional thunderstorms (or 
“seils”? of the Arabs), which in winter burst upon the 
mountains, and send down great torrents of water. In 
traversing the remarkable gorge of the Wady el Ain, we had 
occasion to observe the effects of such floods in piling up 
boulders, shingle, and drift-wood at the headings of the 
valley. 
Recent changes in the climate of Arabia Petreea and Palestine. 
-—This brings me to the last point which it is necessary to 
refer to in this communication, namely, the evidence of a 
former climate more closely resembling that of central Europe 
and the British isles. Although part of this region is gene- 
rally regarded as rainless, this is not exactly the case, as a 
little rain, generally accompanying thunderstorms, falls in the 
winter time, and the summits of the Sinaitic mountains, ac- 
cording to Sir Charles Wilson, have a capping of snow for a 
short period, from which the perennial springs are fed. But 
the climatic conditions must have been very different from the 
present only as far back as the Glacial epoch, when glaciers 
descended the valleys of Lebanon to a level of 4,000 feet 
above the sea. As Sir J. D. Hooker has shown, the grove of 
the venerable cedars decorates the surface of an ancient moraine 
which was thrown across the valley, and was formed at the end 
of a glacier which descended from the snowfields above. It 
may be supposed that at this epoch the annual mean tempera- 
ture of Palestine and Syria was 25° Fahr. lower than at 
present, and that the rainfall was very considerably in excess 
of the present amount. 
The melting of the snows on the Lebanon, and the large 
amount of rainfall may be considered as a sufficient reason for 
the high level at which the waters of the Jordan-Valley lake 
formerly stood, and for the size and depth of many of the old 
river valleys, such as those of the Zelegah and Hl Ain, in the 
Sinaitic Peninsula, I have also ventured to suggest the proba- 
bility that during this epoch the voleanic fires of the Jaulan 
and Hauran were still in activity, the waters of the great 
lake, finding access through the faults and fissures of the 
Jordan Valley, having supplied the steam-power (so to speak) 
now generally recognised as a necessary agent in volcanic 
explosions. If this be correct, then we may further assume 
that with the drying up of the waters and their recession into 
their comparatively narrow bounds, such as they now occupy, 
the volcanic action concomitantly subsided, and ultimately 
Cc 2) 
