Al Deveron wrote:

70% cotton 30% nylon (fairly thin). Is this a good fabric for
canoeing/camping pants (aka trousers!)?

If it's warm enough and you're just out for a two hour excursion, sure
they'll work fine. But if there's a chance you might encounter temps
below about 25 Celsius (75 F) and there's any chance of getting wet,
don't wear cotton anything.

IOW, keep looking. Nylon, polyester, polypro, even wool are all a
better choice than cotton.

//Walt