Forum:Ancient City - Rainbow Ruins vs Other Field Spell

I'm just a little confused 'bout the Ancient City - Rainbow Ruins 3rd Effect. Lore: ''This card gets these effects, based on the number of "Crystal Beast" cards in your Spell & Trap Card Zone. ● 1+: This card cannot be destroyed by a card effect. ● 2+: Once per turn, you can halve the Battle Damage you take. ● 3+: You can send 1 "Crystal Beast" monster you control to the Graveyard to negate the activation of a Spell or Trap Card and destroy it. ● 4+: Once per turn, during your Main Phase, you can draw 1 card. ● 5+: Once per turn, during your Main Phase, you can Special Summon 1 "Crystal Beast" card from your Spell & Trap Card Zone.''

Situation:


 * Player A has 3 crystallized CB in his S/T zone and 2 CB in his Monster zone.
 * Player B, turns to be the Turn Player, activate his A Legendary Ocean field spell.

I already know that you must send 1 CB monster and not the crystallized form. But can I negate the activation of his Field spell card?? or my field spell will be replaced with his?? Thanks in advance!

'''ALL HAIL THE MIGHTY DRAGONS!!!!!--DrAgOn`TaMeR 15:11, 3 June 2009 (UTC)