Identify this 1930 airliner?

Can anybody identify the aircraft in this picture?
http://pgh.aulick.net/1930mysteryplane.jpg

The picture is a scan of the cover of an interesting booklet. It
contains tables of typical airfares for February 1930, an air route map
including an Embry-Riddle airline with one route through Indianapolis
and Chicago, and an ad for "the world's first air-minded hotel". Many
of the routes, even southern ones such as Alabama-New Orleans, are
listed as "not operating in winter"

~Adam Aulick
adam @ aulick.notthisbit.net