Rocky Mountains. 409 



along the base of the Rocky Mountains, and the sandstones 

 of the two districts are often remarkably dissimilar. For 

 these reasons, we have been induced to consider this as be- 

 longing to the group of the O/.ark mountains. I'hese we 

 shall now proceed to describe, according to the information 

 in our possession. 



From an inspection of the map annexed to this volume, it 

 will be perc«^ived, that the Missouri below the mouth of the 

 Konzas is considerably inflected to the east, to pass round 

 the end of a range of hills, rising in the angle between this 

 river and the Mis-issippi. This range increases in eleva- 

 tion for some distance to the southwest, its highest point 

 being in the region near the sources of White and Osage 

 rivers, the two most considerable streams originating in these 

 mountains. Farther to the southwest, losing a part of its ele- 

 vation, it is traversed in succession by the Arkansa and Red 

 rivers from the west, and gives origin to the Washita, the 

 Sabine, and some other rivers of secondary magnitude. 

 Our acquaintance; with the country between Red river and 

 the Rio del Norte, is too imperfect to enable us to trace 

 particularly the continuation of the Ozark mountains, which 

 is believed to extend to that river, and to have some con- 

 nexion with its great southern bend below the confluence of 

 the Rio Conchos. We therefore confine our attention to the 

 portion northeast of Red river. 



Though no point of great elevation occurs in any part of 

 the range, the whole is truly a mountainous region, and well 

 entitled to a distinctive appellation. Its parallelism in general 

 direction, to the Atlantic coast, and to the great chain of the 

 Allckjhanies, together with the character and inclination of its 

 Component strata, aflbrd unequivocal evidence that it be- 

 longs to a system, independent of the Rocky Mountains. In 

 several particulars, a striking resemblance is manifest be- 

 tween this range and the Alleghanies, and in some, as we 

 shall notice hereafter, as strong a dissimilaiity. 



Near the western limits of the Coal Formation, which are 

 also the limits ot the mountainous country on the Canadian 

 and Arkansa, compact limestone occurs for the first time, 

 (as far as our acquaintance extends; on this side the Rocky 

 Mountains. This formation of limestone, and the accom- 

 panying strata of argillaceous sandstone, though they do not 

 perhaps always strictly coincide in position, may be traced 

 far to the north, and these we consider as marking the west- 

 ern limits of the Ozark mountains. It is to be remarked, 

 VOL. II. 5^z 



