Answer:
intrusive igneous rock
Explanation:
A rock that lies perpendicular to the surrounding horizontal strata means that it is lying at a 90 degree angle compared to the surrounding horizontal layers. This type of positioning of the rock layer suggests that it is a younger rock layer which intruded the preexisting rock layers. Such rocks occur because of volcanic activity, when the magma manages to penetrate through the softer rock strata and cut through it, thus disturb it and break its uniformity.