14 GEOLOGY OF THE THIRD DISTRICT. 



In the preceding pages, it will be perceived that the whole of the geological products, 

 usually 80 considered, of the district are arranged under three heads. The first, as rocks 

 and groups, being the simplest result of analysis that with advantage could be obtained ; 

 properly speaking they are geological elements, and as such arc considered. The second, as 

 divisions, and are formed by one or more of the above elements. The third, as systems, 

 formed of the divisions. 



In determining what were the simple or individual rocks or masses, and their arrange- 

 ment, though uninfluenced by the labors of others beyond this State, and our country, yet 

 attention has been fully given to the facts and results made known, from their direct bearing 

 upon the district, knowing the importance which they would have upon a question for exam- 

 ple, like that of the presence or absence of coal in the district. Thus by the arrangement of 

 the rocks in the Pennsylvania Reports, the whole, from what corresponds with the Potsdam 

 sandstone, to the Coal series, both included, arc embraced in thirteen formations. The first 

 nine in the ascending order, extend to the Catskill group inclusive, and are called the Appa- 

 lachian system. The four upper ones, are considered to form the Carboniferous system, the 

 anthracite coal basins fornaing the upper or fourth formation ; the bituminous coal being part 

 of the same formation. A comparison in accordance with the results reported of Pennsylva- 

 nia, show that three formations are wanting in the third district to connect its upper rock 

 with the coal, that being the fourth formation, all which have no existence according to the 

 report in the district. 



In England, there is good reason to believe that the Cambrian system is but the disturbed 

 part of the Frankfort series, or Hudson river group, and that probably neither the Silurian or 

 the Cambrian systems inclusive extend so low as the Potsdam sandstone, nor higlier than 

 the Ithaca group ; the Devonian extending from the Silurian, and embracing the Catskill 

 group, which is its highest known number, the Carboniferous or Coal-bearing rocks, com- 

 mencing at the top of the Devonian system, or the Old Redsandstone, and Catskill group. 

 This result perfectly accords with the facts and conclusions made known in the New- York 

 Reports, the highest rock of the district, being the base of the coal scries, group or formation; 

 and therefore all expectation of finding coal below that point, from all known facts obtained 

 from Pennsylvania, Great Britain, and the State, is perfectly futile. 



To such as are interested in the geology of the west, it may be useful to state that the 

 lowest mass, obsei-ved in the States of Ohio and Indiana for example, belongs to the upper 

 part of the Champlain division of the New-York system, and extends from the Trenton lime- 

 stone to the top of the sandstone shale of Pulaski. It is considered to be one mass ; contains 

 the fossils of those two periods ; the lower part called the Blue limestone, the other tlie Blue 

 marlite. The next mass is the Cliff limestone, which extends upwards to the Marcellus 

 shales, and contains the well known fossils of the Ontario, and Helderberg division. The third 

 extends to the coal ; the Waverly sandstone of Ohio showing tlic same peculiar fucoids, the 

 Cauda-galli, which are found in many parts of the Erie group in New- York. 



The arrangement adopted, in a measure happily accords with several great geographical 

 features of the third district, which are all important to enable one readily to comprehend and 



