OF ARTS AND SCIENCES. 175 



write the " so-called Taconic system," — this expression containing 

 the knowledge of the writer on the question. The other is, carefully 

 to avoid naming the Taconic, even in the manuals destined to pre- 

 sent to the public the actual condition of American geology. 



In the same way one hears geologists say, " I do not believe in the 

 doctrine of colonies " ; or, " I do not believe in the passage of one or 

 more species from one system of strata to another." To deny facts 

 does not suppress them. They are there, in the field, and the only 

 answer is, that those who do not see them are unfortunate. 



" Geological theories, instead of being rigid and irrevocably fixed in 

 their principles, should be framed with great elasticity, to embrace, if 

 need be, unexpected facts. Geology is far from being complete for us, 

 and is slowly forming itself, surmounting the difficulties of observation, 

 and also painfully freeing itself from the hindrances that our limited 

 human intelligence creates for itself by preconceived theories." * 



Geology is not a science to be studied in laboratories, nor by man- 

 uals ; it is by work in the field, in deciphering the manusci-ipt that 

 the earth spreads everywhere before us, that a knowledge of it is 

 attained ; and certain more difficult pages of this terrestrial book re- 

 quire many years, and often several generations of geologists, to be 

 correctly interpreted. In the end, the truth is always victorious, in 

 spite of opposition and obscurity, and therefore the future of the 

 "Taconic System" is fully assured. 



II. Historic : 1837-1881. 



1837. — The "sandstone of Potsdam" was first recognized and named 

 by Dr. Ebenezer Emmons in 1837. In his '' Second Annual Report" 

 as Geologist of the Second Geological District of the State of New 

 York (Albany, Feb. 15, 1838, p. 214), this name first appears, with a 

 description of the quarries of Racket River, near Potsdam villao-e, in 

 the county of St. Lawrence. " Potsdam Sandstone," the designation 

 of a group of rocks since become so celebrated in geology, was first 

 priiittHl on page 217 of the same Report. 



1838-42. — The first appearance of the " T.aconic System " is in 

 tlie " Final Report on the Second District of New York" (Albany, 

 Jan. 1, 1842), of which it constitutes Chapters VIT., VIII., and IX. 

 Dr. Ebenezer Emmons says : " A group or system of rocks which 

 belong evidently to a position between the primary of the Atlantic 



* Barrande, Dc'fense des Colonies. IV. p. 79 (1870). 



