Trapped between the sandstone, the magma cooled very slowly and formed the igneous rock called diabase which makes up West Rock.
(the magma; cooled very slowly; ) (the magma; formed; the igneous rock called diabase which makes up West Rock) (the igneous rock called diabase; makes up; West Rock)
the magma the magma the igneous rock called diabase
cooled very slowly formed makes up
the igneous rock called diabase which makes up West Rock
West Rock