— 
1884.] Geology and Paleontology. 411 
As regards the Cambrian of the fourth area, that of the Cor- 
dilleras, the speaker alluded to the important observations of 
Powell and the recent studies of Walcott. Great local variations 
may here be looked for, and discoveries which will enable us to 
understand better the relations between the Appalachian Cam- 
brian and the other areas mentioned, as well as those on the 
a coast in Massachusetts, New Brunswick and Newfound- 
d. 
THE GEOLOGY OF ALGIERS—-FORMATIONS BELOW THE TERTIARY. 
formation of the mountains. Between these two parallel ranges 
lie an elevated zone of plateaus, which was uplifted at the same 
time. To the south of the southern crest extends an immense 
region through which the strata lie horizontally. This is the Al- 
gerian Sahara. Beyond this, on the confines of the Soudan, traces 
of dislocation appear, with eruptive rocks,and some vegetation. The 
ferent geological strata are disposed in long belts parallel to the 
coast, and the same arrangement obtains in Tunis and Morocco. 
The country is thus divided into zones, bearing each its distinct 
soil and climate, productions and people. The principal axis of 
the Algerian chain is that of the north, and it is this which has 
determined the direction of the Mediterranean coast. Previous to 
the uplift of the mountains, repeated and considerable outflows of 
‘sneous rocks had taken place, but the greatest outflow occurred 
in the Quaternary epoch. A great part of the effects of this plu- 
tonic outburst are hidden beneath the sea, but the northern coast 
of Sicily to the east, and Madeira to the west, are in the line of 
€ basalts of the African coast. The rivers which flow north- 
ward an a 
gorges by which these chains are intersected. The 
Tia Strata are crystalline schists, granite gneiss, mica schist, etc- 
Pe ati upon the coast, and form mountain masses or islands. 
provi € strata are not extensive, but are most developed in the 
Phitic of Oran. Some schists, with vegetable impressions, gra- 
PS Crane etc., are referred to the Silurian, and the pudding- 
of the m conglomerates with polyps, encrinites and foraminifera 
M. <r of Ain-Talba, are referred to the Carboniferous by 
her. The Devonian does not seem to be represented in 
irra et it undoubtedly occurs in Fezzan. No traces of 
, tan have yet been found, and the identification of certain 
