20 TRANSACTIONS OF THE [OCT. 24^ 



the following formations : 1. The Primary, embracing granite 

 (i. e., labradorite rock) and gneiss. 2. The Transition {i. e., 

 Cambro-silurian). 3, The Tertiary or newer Pliocene, {i. e., the 

 glacial clays, etc.). Emmons makes an extended argument to 

 prove the igneous character of certain limestones, and in the 

 report on the iirst district, Mather corroborates the idea. 

 Emmons' second report contains also man}- details about iron 

 mines, and an account of his ascent of Mt. Marcy, Avhich he 

 determined to be 5,4G7 ft. 



The third annual report (1839) describes Hamilton, Clinton 

 and Warren Counties, but is mostly devoted to the discussion of 

 various economic minerals, peat, marl, etc. The fourth report, 

 1840-41, takes np the iron ores at length, especially those at 

 Lake Henderson. 



The final report appeared in 1842. The classification of for- 

 mations is as follows : 

 A — Primary. 



I. Unstratified. 



a. Granite. 



b. Hypersthene rock. 



c. Primitive limestone. 



d. Serpentine . 



e. Kensselaerite. 



II. Stratified. 



a. Gneiss. 



b. Hornblende {i. e., hornblendic-gneiss.) 



c. Sienite. 



d. Talc or Steatite. 



III. Subordinate. 



a. Porphyry. 



b. Trap. 



c. Magnetic and 



d. Specular oxide of iron . 



B — New York Transition System. 

 Champlain Group. 



a. Potsdam sandstone. 



b. Calciferous sandrock, 



c. Chazy limestone. 



d. Birdseye limestone. 



e. Trenton limestone, 

 y. Utica slate. 



g. Lorraine shales. 

 h. Grey sandstone. 



C— Tertiary. 



