Watch Art Cashin: Why lower oil isn't good news

90 Seconds with Art Cashin: If oil's down, the economy could be slowing
Cashin says: If oil's down, the economy could be slowing   

Art Cashin says lower oil prices and falling interest rates could be a sign of a slowing economy and a threat to the stock market's ongoing rally.

Cashin, UBS' director of floor operations at the NYSE, told CNBC's Bob Pisani around midday this is going to be a "very critical week to watch and the earnings come out and the guidance comes out."