Thanks for the Sansa Clip suggestion. It looks like I'll definitely have to buy a compatible device to listen to audible books because audible will not play on just any MP3 player. They're as protectionist and anti-competitive as Australian publishers.
No rock is completely impermeable, but some porous rocks like shale and pumice are mostly impermeable, because the pores are not interconnected, thus not allowing fluids or gases to pass through them. This is why shale makes a good cap-rock, and pumice floats instead of sinking.
An aquifer is a body of saturated rock or sediment through which water can move easily. Highly permeable and saturated with water. Good: sandstone, conglomerate, well jointed limestone, bodies of sand and gravel, volcanic rock such as columnar basalt. Shall usually impermeable.ost sandstones and conglomerates are both porous and permeable. An impermeable rock is the one that does not allow water to flow through easily-like unfractured granite and schist are impermeable. Shale is porous but low permeability(pores too small for water to pass through).