Smaller ranges run parallel to the main mountain chain in many places, and there are numerous isolated spurs which have no connexion with either.
Malta and Gozo are the only islands of the Mediterranean which can be associated with this section, and, per contra, the mountain chain of north-west Africa belongs to Eurasia.
No great mountain chain was ever raised by a single effort, and folding went on to some extent in other periods besides those mentioned.
The strata here show some traces of the upheaval which formed the Appalachian Mountain chain.
Through these Rocky Mountains the explorers and furtraders, by ascending the streams running down the eastern declivities of the mountains, and crossing by short portages to the streams of the western slope, have succeeded in discovering passes by which the mountain chain can be crossed, the range rarely exceeding 60 m.