What kind of morter would i need to make a fairly detailed fountain "mountain"?

Question:made a fairly large frame out of popsickle sticks and crafts store wood. so i have a shell. just what to cover it with that hols water and not clumpy so i can mold astheticly? morter? kind?

Answers:
Use a product called 'Hydra-plug' or hydraulic cement. This is a chemically hardened cement that is smooth when set. Its is also very waterproof. Mix in very small quantities as it sets up in a matter of minutes. You can smooth it on with your hands, but I recommend wearing some type of glove to avoid the chemical that sets the cement.
You will see that it feels hot when mixed , this is from the chemical reaction between the water and the mix.

Good luck.