What does Zinzolin mean by the abyssal?

Question

Sorry for the bad spelling and explaining lol

Answer 1

Okay so the Sage you met I think is Zinzolin. He refers to the Abyssal Ruins which can be located at Undella Bay by using Dive
After defeating the Elite 4 and talking to Zinzolin he gives you Ghetsis's Notebooks which allows you to transalate the writing in the ruins to English assuming your game is in English.

Extra Sources:
http://www.serebii.net/black2white2/abyssalruins.shtml

Answer 2

If you Surf off to the east of Undella Town, you will reach Undella Bay. There are 4 spots on the water where Dive can be used. When you dive, the Abyssal Ruins appear, and inside, you can get every elemental plate, except Dragon and Water, as well as Relic items that can be sold to the maniac in Undella Town for lots of money.