1. The temple is in a "white" city.
2. The temple is in the Near East.
3. The temple is in a "triangle" city.
Taken together, these point to Nepal. This scheme works well and permits a secondary mechanic whereby a player can reveal the clue he just read to the other players, in exchange for some action cards; but the structure of the clues is such that reading a given level doesn't give away complete information to the other players.
But in some cases, this composite construct seems forced. Consider how we would construct clues for the length of the Staff of Ra in Raiders of the Lost Ark, which is crucial in determining where to dig for the Well of Souls. In the composite approach, it might look like this:
1. The staff is at least 4 feet tall.
2. The staff is at most 7 feet tall.
3. The staff is not 5 feet tall.
Again, this is functional, but it just doesn't ring true as the way information about the staff would really appear in the books, tomes, interviews, etc, that Indy would use to gather information -- it's rather forced and artificial. What if, instead, the clues "climbed"? Consider again the same clue, in a different scheme:
1. The staff is (at least) 4 feet tall.
2. The staff is (at least) 4 feel tall.
3. The staff is (at least) 6 feet tall.
The level 2 clue isn't a typo -- what this idea conveys is that instead of each clue giving partial information, each clue may have the full solution. You only know for sure if you go all the way to the level 3 clue, but you may not have to -- a level 1 clue may be sufficient.
Consider how this could enable a more story-like structure to the location clues:
1. The artifact was carried out of the Holy Land by a Franciscan monk to the desert north of Cairo...
2. ...whereupon it was carried across the desert to Marrakech...
3. ...and there may it sit until our Lord returns.
To make this approach work, there would have to be some cards where the level 1 clue really does point directly to the solution, some where the level 2 clue does, and some where only reaching the level 3 clue leads to the solution. Maybe the distribution is roughly 33% of each, or maybe it's 25%/37.5%/37.5%, not sure.
Now the difference between these approaches is subtle but important; in the composite approach, the clues help the player to narrow down the possibilities, so if he acts on partial information, it is based on a guess, and the goal of the game is to maximize the odds that your guess will be accurate by accumulating as many clues as you can. In the climbing approach, the clues lead the player toward the solution step by step, and the guesswork comes more from how far up the clue chain you need to climb to have correct information. Because the game is a race, time spent chasing down "extra" clues is time wasted, but if you don't chase down those clues, you risk having incomplete information. I think the climbing approach is more thematically consonant -- you could end up digging in the wrong place, but not because you guessed wrong on a 50/50 guess -- rather, because there was more information out there than you realized.
Again, this difference is subtle, but I also think the latter approach is more amenable to enabling the players to get additional information from hunches via "relevance" (see the next post), or from "local rumors" (maybe the next post after that...). By piecing together the clues and little pieces of additional information, players may be able to develop a good feel for whether a given level is the final clue or if there are others that follow it.
Gameplay-wise, I especially like the way this potentially focuses importance on the level 1 clues, which are mostly useless at present.
Of course, it could be possible to use both approaches, and letting the situation dictate which is appropriate. For numeric values (the height of the staff of Ra, the weight of the idol in the Chachopoyan Warriors temple), climbing clues make the most sense; for other categories (challenges in the temple), composite clues may be more appropriate.