The Arkansa, having a direction nearly east and west, has no great variety of climate to traverse in its course from the mountains to the Mississippi; consequently there is no succession of thaws taking place upon the river, calculated to maintain a freshet for any considerable length of time. The freshets are occasioned by a simultaneous melting of the snow throughout the whole extent of the river, and by showers of rain, which, falling upon a rolling surface, is quickly drained off, and causes sudden, but seldom excessive rises in the river. I have witnessed, in the Arkansa, no less than three considerable rises and falls of the water in the course of two weeks. The most considerable streams tributary to this part of the Arkansa are the Negracka or Red Fork, and the Newsewketongu, or Grand Saline, on the south, and the Little Arkansa and Stinking Fork on the north side. The Negracka rises within fifty or sixty miles of the mountains, and after meandering eastwardly between four and five hundred miles, unites with the Arkansa at the distance of about nine hundred miles from the mouth of the latter. The Newsewketongu has its source in the plains between the Arkansa and Canadian rivers, and unites with the former about one hundred and fifty miles below the Negracka. The head waters of the Little Arkansa interlock with those of the Smoky-hill Fork of the Konzas, and are discharged into the Arkansa, about fifteen hundred miles above its mouth. The Stinking Fork rises amongst the head-waters of the Neosho, and enters the Arkansa about eight hundred miles from its mouth. Besides these, there are many other streams of smaller size entering on both sides of the river. The Canadian rises at the base of the Rocky Mountains, and after a meandering course of about {231} one thousand miles, enters the Arkansa at the distance of about five hundred and fifty miles from the mouth of the latter. This river has generally been represented, upon the maps of the country, as having a north-easterly course; whereas its source is nearly in the same latitude as its confluence with the Arkansa, consequently its general course is nearly east. In its course, it forms an extensive curve to the southward, leaving a broad space between it and the Arkansa, in which several streams, many hundred miles in length, tributary to both of these rivers, have their origin and course.