The Rio Grande was the major route prior to the Panama Canal.
Answer:
the principle of original horizontality and the principle of superposition
Explanation:
The <em>principle of horizontality</em> states that layers of sediment are originally deposited horizontally under the influence of gravity.
The <em>principle of superposition</em> states that the oldest layer layer is at the bottom and each layer above it is younger, with the youngest being at the top.
Unconformities help us find the age of different layers. An unconformity is a surface in which no new solid matter is deposited after a long geologic interval. <em>Angular unconformity </em>is a type of unconformity which different kinds of stratum were tilted or folded before deposition of younger layers of solid matter above the unconformity. Once the layers were folded and tilted, the older layers of the solid matter eroded, then the younger layers were deposited on the older layers. There <em>angular unconformity </em>is the contact between young and old layers of solid matter.
Therefore, these two principles therefore describe how the tilted layers are older than horizontal layers.
