Why does calcite fizz when it comes in contact with hydrochloric acid?

$\text{Calcite}$ is mineralized $C a C {O}_{3}$, and so..............
$C a C {O}_{3} \left(s\right) + 2 H C l \left(a q\right) \rightarrow C a C {l}_{2} \left(a q\right) + {H}_{2} O \left(l\right) + C {O}_{2} \left(g\right) \uparrow$