Here's why:
* Sedimentary Rocks: Sandstone is a sedimentary rock, meaning it forms from layers of sediment (like sand) that accumulate over time.
* Time and Deposition: As sediment is deposited, it builds up in layers, with the oldest layers at the bottom and the youngest layers on top.
* Compression and Cementation: Over time, the weight of the overlying layers compresses the sediment and minerals within the water seep in, cementing the grains together to form solid rock.
So, the layers at the bottom of a sandstone formation represent the oldest layers, as they were deposited first and have been buried beneath newer layers ever since.
