JEFFERSON COUNTY. 371 



From llic interior of the coiinlics, the rivers flow in direct or nearly direct courses, governed 

 in their general direction by the general slope of the country through which llicy pass ; but 

 on reaching the district of the sedimentary rocks, they meet with a scries of longitudinal 

 fractures which govern the remainder of their route. What other cause could produce such 

 a parallelism in all the rivers and creeks ; in those, for instance, which carry a quantity of 

 water insufficient to break over the small or low barriers between which they flow? The 

 larger streams, from the same cause, ])ursuc the most devious paths possible ; flowing, during 

 a part of their course, in channels previously marked out for them ; but, in consequence of 

 carrying a large amount of water, they sweep across these low barriers, and pass, in the 

 course of their route, through several of the intervening valleys. The great bends in the 

 Indian, Oswegatchie and Black rivers, and the curvatures of the De Grasse, Racket and St. 

 Regis rivers to the north, arc all produced by like causes. In these remarks, I leave out of 

 view the channels of the St. Lawrence, as I propose hereafter to treat of the subject in a 

 more general view, when the facts and hypotheses in relation thereto will be given in full 

 detail. 



In the preceding section of my remarks, I pursued a course different from that which I 

 had marked out, yet I deem it inexpedient to return to the plan 1 at first proposed. I shall 

 therefore merely add, that my great object was to describe the surface of Jefferson county so 

 as to present in a true light some of the changes which its present surface has undergone. 

 This has been done only generally ; but a glance at the map will be sufficient, in connection 

 with these remarks, to satisfy the most skeptical that they are founded in fact. Undoubtedly 

 many interesting facts bearing upon this subject will be furnished from numerous localities, 

 when tlie attention of observers is drawn to the subject. 



Division of the county according to its rocks ; their succession, and the jjeculiar features 



resulting therefrorn. 



There is a beautiful arrangement of the rocks of this county, such as very rarely exists : 

 Here the New- York system commences, on the borders of St. Lawrence county, and the suc- 

 cession continues uninterrupted from the Potsdam sandstone up to the base of tlie Carbonife- 

 rous system. It is here we find that gentle inclination of the rocky masses to the south, 

 which, fortunately for science, is unbroken and undisturbed for two hundred miles, or at least 

 never so much so as to obscure in a material degree the order of succession. 



Of the entire series which enter into the New- York system, Jefferson takes in but a single 

 group, which group is made up of the following members, namely, the Potsdam sandstone, 

 Calciferous sandrock, Birdseye limestone. Marble of Isle La Motte, Trenton limestone, Utica 

 slate, Loraine shales, and the Grey sandstone. 



The order of succession of these several masses is as follows : Upon the north, the Pots- 

 dam sandstone extends four miles south of Theresa falls, where it is succeeded by the 

 Calciferous sandrock and the Birdseye limestone in their usual order, whose southern limit 

 may be defined by a line drawn from Carthage to Brownville. From thence the Trenton 



