No. 5.] DAWSON— LIGNITE FORMATIONS. 245 



their expedition on the Missouri in 1804, mention somewhat 

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

 tion. Many other explorers have since that time noticed the 

 occurrence of this lignite formation even as far south as the Ar- 

 kansas River, but till the inception of the trans-continental rail- 

 way, it was thought of as lying too far west to be useful. The 

 explorations connected with the railway and its construction, and 

 the simultaneous growth of an important gold and silver mining 

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

 rations of Hayden and other geologists, have brought the great 

 Lignite Tertiary Basin of these regions to notice in a manner 

 commensurate with its importance. The lignite coals of this 

 formation are now very extensively worked in several places 

 near the line of the Union Pacific, and are found to subserve 

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

 Carboniferous f.rmation. They are used on the railways, and 

 also for the metalluriiical treatment of ores. 



The region ex mined by me during the latter part of last 

 summer, lies i'^v the most part immediately north of the Inter- 

 national Bound .rv. which crosses the continent from the Lake of 

 the Woods to the Pacific Ocean, on the 49th parallel of latitude. 

 Of the country through which the line passes, about 300 miles 

 from East to West, h ive remained unknown even geographically 

 until explored by the Boundary Survey during last summer, 

 and the Lignite Tertiary formation described in this paper lies 

 almost entirely in this hitherto unvisited region. 



In proceeding westward from Red River, the Cretaceous beds 

 already mentioned are met with in the region of the escarpment 

 called Pembina Mountain, and in the streams which flow dowD 

 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 underlying; 



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 



