GEOLOGY OF THE THIRD DISTRICT. 



CHAPTER IV. 



TACONIC SYSTEM, OR INTERMEDIATE PERIOD; 

 (A name given by Dr. Emmons, /row the mountain range at the east boundary of the State.) 



The want of parallelism between the layers, beds or divisions of the Primary and the New- 

 York system, proves a derangement of the first anterior to the deposition of the latter; and 

 the rugged or rounded outline, and the. smooth surface of the primary at the uplifts where un- 

 covered, shows it to have been water worn before the deposition of the succeeding class. 

 This fact is important, proving that the chain or series of rocks in the third district are not 

 complete, and that masses are wanting to fill the intermediate space. To the period which 

 elapsed between the two systems, we should pljce all those parts of the Cambrian system of 

 England, which hold a position inferior to the Potsdam sandstone, should any there exist ; for 

 from observation here, a Cambrian system could occupy none other than the vacant or inter- 

 mediate space, unless of a particular character. 



Products of the Taconic System, or Intermediate Period. Upon the primary at the north- 

 east of Lewis county, occasionally patches are met with which belong to this period ; they 

 were noticed in the Reporf of 1840. They consist of lamellar white limestone with specular 

 iron ore, and of compact red iron ore ; these occur near Lewisburg furnace, and in the neigh- 

 borhood of Harrisville. From the lower part of the Potsdam sandstone enveloping the same 

 kind of ore, and covering such masses, a connection between the two exists, the sandstone 

 being the terminal deposit. -. 



To this period also the plumbagine rocks at Mr. Cleaveland's, in Lewis county, are to be 

 referred, the whole being obviously what are termed metamorphic rocks, in its proper accepta- 

 tion. These rocks will again be adverted to under the head of Lewis county. At present 

 we would merely observe, that great obscurity exists with respect to them in the district ; but 

 probably full light will be thrown upon them from observations in the adjoining one, or further 

 to the east. The surface of the rocks of the Primary system was without doubt deranged 

 and water-worn, before the products in question were deposited upon it ; the confirmation of 

 which is the covering of a mechanical deposit in the Potsdam sandstone and its conglomerate, 

 being the products of broken up and water-worn preexisting rocks. The chief obscurity arises 

 from the connection of the same ore, and other products, with the two surfaces, which may 



