Both volcanic layers are flat lying, and were erupted on an ancient erosion surface of red gneissic granite, the reddish rocks on the shore.
(Both volcanic layers; are; flat lying) (Both volcanic layers; were erupted; L:on an ancient erosion surface of red gneissic granite)
Both volcanic layers Both volcanic layers
are were erupted
flat lying
L:on an ancient erosion surface of red gneissic granite