But in places the lava flows are separated by sedimentary rock (formed of sediments laid down by water, and later hardened by pressure.)
(the lava flows; are separated; by sedimentary rock; L:in places) (sedimentary rock; formed; of sediments) (sediments; laid down; by water) (the lava flows; hardened; by pressure; T:later)
the lava flows sedimentary rock sediments the lava flows
are separated formed laid down hardened
by sedimentary rock L:in places
of sediments
by water
by pressure T:later