Square numbers which remain squares with the last digit removed

SquaresAndTS.hs

isSquare :: Integer -> Bool
isSquare x
  = root ^ 2 == x
    where
      root = floor $ sqrt $ fromIntegral x

isTruncatedSquare :: Integer -> Bool
isTruncatedSquare x
  | x < 10    = False
  | otherwise = isSquare $ x `div` 10

isSquareAndTS :: Integer -> Bool
isSquareAndTS x
  = isSquare x && isTruncatedSquare x

numbersWhichAreSquaesAndTS :: Integer -> [Integer]
numbersWhichAreSquaesAndTS n
  -- post: returns numbers, up to and including n, which are both
  --       squares and truncated squares
  = filter isSquareAndTS [1 .. n]