The most ancient part is formed by the remains of stratum-volcanoes, which were to the west of the islands and make up "The Timponi", "Monterosa" etc.
(The most ancient part; is formed; by the remains of stratum-volcanoes) (stratum-volcanoes; were; to the west of the islands)
The most ancient part stratum-volcanoes
is formed were
by the remains of stratum-volcanoes
to the west of the islands