18 GEOLOGY OF THE SECOND DISTRICT. 



CHAPTER 11. 



Some of the objects of Geology stated. — What was known of the geology of the Second District at the commence- 

 ment of the survey. — General views of the primary and sedimentary rocks, and an outline of their bounda- 

 ries. — Potsdam sandstone, one of the most ancient of the deposits from water.— Classification. — Term 

 Transition ; no valid objection to its use. 



The topography of the Second District having been given in as mucli detail as seems to 

 bo required, I shall now proceed to the consideration of those subjects and inquiries which 

 are more intimately connected with the objects of the survey. In order that no misappreheia- 

 siou may exist as it regards those objects, I propose to state them under the following heads : 

 1st, To determine the kinds or the species of rock ; 2d, Their arrangement or order of super- 

 position ; 3d, The ores and minerals which are their associates ; 4th, Their agricultural cha- 

 racters ; 5th, Their value as objects of merchandise ; and 6th, Their extent or geographical 

 range. 



The objects which I have now enumerated do not, however, comprise all within the field 

 of geological investigation, or cover tiie ground which is conceded to geological inquiry ; tliey, 

 it is true, arc numerous and highly important, and stand in intimate connection with the wants 

 of civilized life, and become more and more so with every step in the progress of society ; 

 yet, in addition to these, there are other facts and inquiries in geology which do not stand se- 

 cond to any in interest and importance, in the field of human research. The inquiries here 

 alluded to, relate principally to the history of the earth, the organic beings entombed in its 

 solid rocks, as well as the present occupants of its surface, including even man ; and these, in 

 consideration of tlie interest and the bearing they may have on the decision we may make on 

 some of the most interesting questions which daily present themselves to us, will form sub- 

 jects of discussion and reference, whenever they naturally come up, and when they flow from 

 facts which have fallen under my immediate observation. 



Before I proceed to these subjects, which, as I have just stated, form the principal objects 

 of the survey, I propose to state, briefly, what was known of the geology and of the topogra- 

 phy of the Second District, when the survey was undertaken. This appears to be not only 

 just and right to those who interested themselves in the work, but also to myself ; inasmuch 

 as the facts and discoveries whicii have been made public in the annual reports, in verbal aitd 

 written communications, have been copied into many of the publications of the day, without 

 a notice of the source from whence they were derived. This is stated, however, not in the 

 way of complaint, but for the purpose of setting the matter right, though it may be considered 

 by some as one of small importance. Previous to the year 1S37, nothing exact was known 



