What is it 2

what could it be?

I am large I am not small

but I am not so very tall

In fact I'm low down if you will

too low to avoid a spill

I am a resource all can see

and many live alongside me

I am the worlds greatest vault

but I'm worth less than table salt

the answer if you havent guessed

is a plain one I must confess

hidden deep within my rhyme

the clues will wait for the end of time

but now I simply have to ask

were you able to complete the task?

what am I?

Author's Note

please leave a guess so I know if I should do more riddles
Thanks

Reviews

[Rachael]

I'm thinking air or something; but I know that's not right..

[Zeitgeist Manifesto]

Awesome riddle, but im stumped.