IT is difficult to say what is jazz and what isn’t.

Some purists might exclude the music of saxophonist Snake Davis, on the grounds that he plays a kind of funk that crosses over into soul, rock, pop and even New Age.

Often his numbers, having locked into a groove, stay close to the melody throughout, without the lengthy rounds of abstract, improvised solos that are the hallmark of conventional jazz.

And his style of playing – highly emotional and demonstrative – has a pop sensibility; he has been the sax player of choice for a roster of leading chart acts.

Having said that, Davis is a fabulous player and his set yesterday, which closed Marsden Jazz Festival, had plenty of high energy improvisation, from the leader – on tenor, alto and soprano – and from keyboardist Paul Birchall, who had several exciting and extended workouts.

There were some moments you definitely wouldn't get at a straight jazz gig, such as the hint of New Age Celticism, when Davis played tin whistle (very effectively), or some Japanese mysticism on a number using the haunting shakuhachi flute.

But anything that adds to the rather limited tonal palate of jazz is welcome.

Bassist Neil Fairclough and drummer Brian Har-greaves gave the band a funky foundation that had the audience howling for an encore.