Book 84 of the Boxcar Children. This mystery is more of a treasure hunt, but there are strange things a foot. There are a couple of things that make it hard on this one, such as them being there at exactly the right time of year with an ancient clue showing up at exactly the right time. This is one of the less believable in the series and I feel relies heavily on a substantial suspension of disbelief. Aside from that it is a nice read and I did enjoy it.