A batholith is a mass of intrusive igneous rock that forms when magma due to volcanic eruption cools down and deposits in deep layers of earth crust and this mass remains unexposed as it is deposited with several layers of overlying strata. Therefore, the physical structure of batholith consist of lens-shaped mass of magma that is covered by overlying layers of strata, providing it an arch shape.
The way I learned this was with the word "GCAT". G pairs with C and vise-versa and A pairs with T and vise-versa. This is how you know what the opposite chain of DNA will look like.
