안녕하세요.

Eluviation refers to the movement of organic minerals downwards through leaching, 

the dissolving of materials in water.

The E horizon that forms in soil layers refers to the light band of soil that appears in very old soils

because of the high concentration of sand and silt, and very low concentration of organic matter.

E horizons are always found sandwiched between the A and B horizons.

B horizons contain a high concentration of clay, iron compounds, and organic matter that have leached from upper soil layers.

Commonly referred to as the subsoil, this is different from the upper A horizon because

the A horizon is much more darker and contains much more organic matter.

So rather than thinking of E horizons forming from the leaching of materials from the A horizon,

instead, think of E horizon as what's left over after leaching occurs, 

moving water-soluble compounds downard creating the bottom B horizon.

hope this helps :D