NATURAL HISTORY REPORT ON WESTERN DIVISION. 219 



on the north, up to the very shores of the sound, and on the south covering, in a similar manner, 

 all the country limited on the west by a broken line drawn from the sound to a point on the 

 Columbia a few miles below Cape Horn. The eastern range, as we have seen, throws out high 

 spurs between the Yakima and its branches, covering all the country north of this river up to the 

 Columbia. As there is another high range running northeast from the mouth of the Klikatat, and 

 only terminating with the Columbia after coursing the Yakima, from six to ten miles to the south 

 of it, we may safely infer that most of the country between it and the northern river-range of the 

 Columbia is either mountainous or high, broken table-land. The country east of the Okinakane 

 river, and north of the Columbia, having been found mountainous, the Columbia river may be 

 taken generally as the eastern limit of the mountains, or of high mountainous country. The main 

 range, and all the territory west of the range, are heavily timbered with pine, fir, larch and cedar. 

 The eastern limit of timber is the Columbia river from Fort Okinakane to the mouth of the 

 Wenatsbapam, a right line from that point to the forks of the Sahpenis, and a right line thence 

 to the Dalles of the Columbia. The soil throughout is uniformly light, shallow and sandy* 

 and most of the country is sterile, barren and desolate, unfit for the purposes of agriculture, 

 in its present state, and incapable of being reclaimed. The rivers are all mountainous in 

 character ; currents rough and rapid, and beds stony. The variation of the needle is east. This 

 variation decreases from the coast as you proceed eastward to the main Cascade range ; beyond 

 which, in the same direction, it increases as you proceed. I am not aware that any exact ratio 

 exists in this increase and decrease. The following examples will give some general idea of the 

 state of increase and decrease: 



At Oly mpia, the variation is 21 



At Fort Vancouver, the variation is 19 45 



At Chequoss, the variation is 16 5 



At Ketetas, the variation is 17 34 41&quot; 



At Wenatshapam, the variation is 18 50 27&quot; 



And it similarly increases towards the east. The minimum is about 16. 

 I am, very respectfully, your obedient servant, 



J. K. DUNCAN, 

 Second Lieutenant 3d Artillery. 



Capt. GEORGE B. MCCLELLAN. 



9. NATURAL HISTORY REPORT OF DR. j. G. COOPER, NATURALIST, OF WESTERN DIVISION. 



General Notes on the Natural History. 



SIR: The country traversed by your division presents several well defined and very distinct 

 zoological and botanical regions. 



The limited time of the survey, and the extent of country traversed, do not afford sufficient data 

 for defining the limits of these regions and their peculiar products with accuracy, but I will 

 attempt, in the following sketch, to give some idea of their outlines. 



It will be observed that there are two great regions very distinct and peculiar in their products, 

 both animal and vegetable, that of the forests arid that of the plains. The first of these is divisible 

 into sub-regions for example, the alpine summits of the mountains and the small prairies. The 

 second also presents several sub-regions for example, the rocky hills and the sandy valleys. 

 The rivers and their immediate banks form a region which differs but little in products on either 

 side of the Cascade mountains nil those met with being tributaries of the Columbia. All the 

 above sub-regions differ more or less in the animals and plants peculiar to them, as may be 

 seen from the collections made, and the notes in connexion with each of them. 



