This may contain SPOILERS.
While strolling through the FF wiki this came to me. Deep Sea Deposit is the ruins of a location from FFVII, most likely City of the Ancients. I'll try to keep why I think so, short.
1. The FF wiki states on the draw point page (i think its that page, but it does state it somewhere), that somewhere in the FFVIII world, there is an extremely large draw point. It says that the researchers at the Deep Sea Research Centre were looking for this specific draw point.
Now, FFVIII was created after FFVII, so FFVII would have been fresh in the minds of the creators. Draw points are a reference to the lifestream. Materia is known to materalise from the lifestream and you can draw magic from draw points. Therefore, draw points is the lifestream.
2. After you get passed the last steam door in the Deep Sea Deposit, there is a lot of old ruins that you traverse before you get to the bottom. These have a resemblence to the City of the Ancients. (take note to sea shells, etc)
3. In FFVII, it states that the WEAPONS, sleep deep inside the earth. The final boss in the Deep Sea Deposit is right at the bottom, and this location is quite deep in the FFVIII world, right underneath the ocean. Close to the core of the earth (FFVII)
4. Ultima Weapon has Cloud's Ultima Weapon.
So, what do you think?
Subtling done on purpose by the creators? I think they intended draw points to be an offspring of the lifestream.