Its mountains, which belong to the Adriatic watershed, and form a continuation of the Montenegrin highlands, are less rounded and more dolomitic in character.
In the Rennes basin limestones - often dolomitic - are associated with quartzites and conglomerates; silicious limestones also occur in the Sarthe region.
They rise for the most part at the foot of the Calvarienberg (1070 ft.), which is composed of dolomitic limestone, and are mostly used for bathing purposes.
The contrasts could hardly be more extreme; stark vertical rock faces and jagged spires of dolomitic limestone hang high above green forested valleys.