In this fashion we "groped" our way with considerable rapidity. Guided by the waggon tracks--especially when there was a moon--we could travel almost as fast as by daylight. Only upon dark nights was our progress retarded; but, notwithstanding every impediment, we were enabled to travel faster than the caravan, and we knew that we were rapidly gaining upon it. We could tell this by the constantly freshening trail; but we had a more accurate criterion in _the count of the camps_. By the number of these, we knew to a certainty that we were approaching the caravan. We were in high hopes of being able to come up with it, before it should enter the mountain-passes--more dangerous to the traveller than even the plains themselves: because at that season more beset by bands of marauding savages. Under the influence of these hopes, we were pressing forward, with all the haste it was in our power to make; when our journey was varied by an incident of a somewhat unexpected character. CHAPTER FORTY ONE. AN UN-PRAIRIE-LIKE APPARITION. The incident referred to occurred high up the Arkansas, at the celebrated grove known as the "Big Timbers." We had started about two hours before sundown, and were riding in a due westerly direction, over a "rolling" prairie--the ridges of which, as ill-luck would have it, ran transversely to our course: causing the path to be constantly going upward or downward. It was not this that troubled us; but the fact that, as we crested each swell, we were freshly exposed to observation from a distance; and this recurring so often, kept us continuously on the alert.