^O- 5.] DAWSON— LIUNITE FORMATIONS. 245 



their exposition ou the Mis.souri in 1804, mention soniewlmt 

 fully the occurrence and distribution of the rocks of this forma- 

 tion. Many other exph»rers have since that time noticed the 

 occurrence of this li-nitj formation even as far south as tlie Ar- 

 kansas River, but till the inception of the trans-con.inental rail- 

 way, it was thou-ht of as lying too far west to be useful. The 

 explorations connected with the railway and its construction, and 

 the simultaneous -rowth of an important -old and silver '-ining 

 region in Nevada and other western territories, with the explo- 

 rations of HaydiMi and other gvologists, have brought the great 

 Lignite Tertiary Basin of tliase regions to notice in a manner 

 commensurate with its importance. The lignite coals of this 

 formatiot. are now very extensively worked in several places 

 near tlie lino of the Cnion Paeifie, and are ibund to subserve 

 all the ordinary purposes of the more perfect coals of the true 

 Carboniferous formation. They are used on tl»e railways, and 

 also tor the mctailiirgical treatment of ores. 



The region . x n.ined by me duri.ig the latter part of last 

 summer, lies Wn- il.c most part immediately north of the Inter- 

 national 13ound IT, which crosses the continent from the Lake of 

 the Woods to the Pacific (3ceai,, on the 4!3th parallel of latitude. 

 Of the country through which the line passes, .bout 300 miles 

 trom Last to West, have remained unknown even geooraphically 

 until explored by the Boundary Survey during last summer, 

 and the Lign.te Tertiary formation described in this paper lies 

 almost entirely in this hitherto unvisited re-ion. 



In proceeding westward from Red River,''the Cretaceous beds 

 already motioned are met with in the region of the escarpment 

 called Pembina Mountain, and in the streams which flow down 

 over It, and occasional exposures of these rocks are found for a 

 distance of about 45 miles. Beyond this, for about 150 miles 

 no rock exposures whatever are to be seen in the vicinity of the 

 Line, the whole surface of the plains being composed of drift 

 materials and marly sands and gravels. The river valleys are 

 deep and broad, but the banks are grassed from top to bottom, 

 and though very generally strewn with boulders belonging to 

 the drift formation, do not show any sections of the underlvin*^ 

 rocks. ^ "* 



At about 240 miles west of Red River, the boundary line 

 strikes the Lignite Tertiary formation ; the prairie level rises 

 at the same place by a gentle step, which may be considered as 



-rr xr 



