154 
Rev. H. B. Tristram on the 
geological characters. This is peculiarly the case with respect to 
Northern Africa strictly so called, i. e. the Barbary States—the 
‘Mogreb* of the Arabs—extending from the Gulf of Cabes, south¬ 
east of Tunis, to the bold headland in which the western Atlas 
range abruptly terminates on the Atlantic coast of Morocco. If 
we cast our eyes on the map of Africa, we shall see no portion of 
the globe apparently so compact, so self-contained. A penin¬ 
sula, attached only to Asia by a narrow isthmus, Africa exhibits 
no islands like those which encircle Europe, -struggling, as it 
were, to be freed from the continent. No deep gulfs and bays 
indent her shores. Compact and solid, the geological convul¬ 
sions which have dislocated Europe have met with an impene¬ 
trable barrier in the ridge of the Atlas, which has sternly 
repelled every encroachment. We might naturally expect then 
to find the Eauna and Flora of Africa throughout characteristic 
and homogeneous, or, at most, varied only by the effects of cli¬ 
mate and latitude, like those of Asia and America. 
But when we examine more closely the physical geography of 
Africa, we shall find that, so far from this being the case, the 
natural history of the Atlas bears scarcely any affinity to that 
of the rest of the continent, and that this distinctiveness may be 
at once traced to natural physical causes. To the naturalist, 
North Africa is but a European island, separated, it is true, 
from Europe by the Mediterranean, but far more effectually 
isolated from Central Africa by that sea of sand, the Sahara. 
The Atlantic isolates it on the west, while a comparatively 
narrow, but most impenetrable desert of ever-shifting sand cuts 
it off from Tripoli and Egypt, which on their part seem to bear 
rather on Asia than Africa. No link attaches Barbary to the 
rest of the continent, no river supplies an arterial communication, 
not the most insignificant streamlet forms either a bond of union 
or a frontier line; the long Atlas chain abruptly terminates in 
Tunis, and sends not one solitary spur towards Africa; it rather 
seems by one of its branches to claim kindred with Europe. So 
far the Arab geographers are accurate in coupling ‘ Mogreb 3 
with Europe instead of Africa. They, too, have the tradition 
mentioned by Livy, Pliny, and Seneca, that Spain and Morocco 
were once united,—-an idea which must so naturally suggest itself 
