Zebra, hate to burst your bubble, but you also didn't do it properly, as you missed a key tile or two. Probably because the combos aren't set up in Pure Rememberance for those two tiles that are included, but that's just a nitpicky thing.
Yoshidude, those special cliff-edge-meets-cliff tiles are kinda meant to be used to show that hey, the ground ends here, there's more mountain going downward. It also helps with depth as well to extend the mountain down at least one more combo on the respective sides of the tile. Here is a screenshot of a more recommended way to use the tiles.
I have used the basic layout of your mountains on that screen to help guide you in resolving the problem, note that I've also brought down the corners near the bottom of the pond closer to the edge of the screen, while something like this isn't recommended, it's still useful in making sure your water combos look proper, but that's up to you how you want to design it. However, as you can notice, the waterfall is slightly longer due to the additional layer added in, but I think it looks better this way.