But their progress was far more slow and toilsome than they had anticipated.

Dense forests were to be threaded, where it was necessary for them to cut their way through almost tropical entanglement of vegetation.

Deep and broad marshes were to be waded, where the horses sank almost to their saddle-girths.

There were rivers to be crossed, which could only be forded by ascending the banks through weary leagues of wilderness.
Thus, when twenty-eight days had passed, and their provisions were nearly expended, though they had for some time been put on short allowance, they found that they had accomplished but three-quarters of their journey.

Actual starvation threatened them.