For one thing there aren't any of those little nubbin holes available except on the true original horizontal surface.
So let's talk about ordinary wooden blocks, simple cubes with no little nubbin holes. What prevents me from stacking and restacking the blocks ad infinitum? How do the blocks even know whether they're being stacked on the "original" layer? And why would they care?
Yes indeed, they will. It's called "erosion". That's how the surfaces get flat if they weren't initially deposited flat.
So, since you agree that I can deposit more blocks on top of the Block Column, what's your idea about the geological column "stopping"? The grains that make it up are just smaller versions of my blocks.
What's the difference? If I can put a block on top of the pile - even if it slips to a new location - why can't natural forces put a grain of sand on top of the pile - even if it slips to a new location?
It is not still a column if it continues anywhere but ON the vertical structure.
Well, a Greek column that falls down is still the same column; it's just lying horizontally.
You're taking the word "column" to literally. The "geological column" just means a cross-section of the layers at any point. Some layers are wider than others - some cover whole states, others are just a hole filled with sediment. Some layers get bent or cracked. Some get tipped on their sides like a Greek column. Some are partially or completely eroded away.
Wherever you look you'll get a different cross-section.
The strata are sedimentary rock. Lava doesn't form strata.
Suppose there's a flood that leaves layers of sediment. Then lava flows down and covers the sediment. Later, another flood deposits more sediment on top of the lava. The lava is a continous layer, part of which is horizontal and part of which is not.