Daily Express Crusader 17.12.10

[Scothern 20]

Crusader, 17.12.10.
15 across. Marsupial makes a local act badly. I've got n-t-v- --t, could it be native cat ?
16 down. a race isn't developing to find a well. Could this be cartesian well ? (anagram)
Thanks in anticipation. Cheers. Barrie

[bibblebub]

15a yes native cat seems fine http://www.thefreedictionary.com/native%20cat

[bibblebub]

There is such a thing as an artesian well but not a cartesian well, although the clue does suggest the latter - how many letters?

[Scothern 20]

There are 9 letters. I have c-r-e-i-n

[bibblebub]

must be cartesian - maybe it's a common malapropism in some parts of the country