MAGNETITE IRON DEPOSITS OF SOUTHEASTERN NEW YORK Tl 
PARTI 
BRIEF HISTORY OF THE STUDY OF HIGHLAND 
GEOLOGY: AND THE MAGNETITE ORES 
The geology of the Highlands has been a subject of study and 
speculation for many years, partly because of the striking character 
and imposing grandeur of the scenery, partly because of the won- 
derfully complex nature of the rocks, and in no small degree because 
of the fascinating possibility of finding useful metals and minerals 
hidden in its formerly little-known fastnesses. 
Probably the earliest account of Highland geology was written by 
Samuel Akerly, who published in 1820 an essay of 69 pages on the 
geology of the Hudson river, illustrated by a geological cross section 
of the country from the neighborhood of Sandy Hook, N. J., north- 
ward through the Highlands in New York, toward the Catskill 
mountains. 
This was followed by a paper on the geology of the Highlands, 
written by Amos Eaton * who was connected with the military aca- 
demy at West Point. Eaton determined the “ middle portion” of 
the Highlands, for 5 miles north and south of Buttermilk falls, to 
be gneiss and granite, which were succeeded in a northerly and 
southerly direction by “ hornblende rock,” which in turn was suc- 
ceeded by “ transition argillite.” 
One of the most illuminating of the early studies is a paper by 
Vanuxem and Keating,? who describe the rocks associated with the 
zinc ores at Franklin Furnace, N. J. A correct description is given 
of the angular unconformity between the “ graywacke” (Hardy- 
ston quartzite) and the “Sienite” (Pochuck gneiss); the “blue 
limestone’’ is correctly determined as younger in age than the 
“ primitive limestone” (Franklin limestone). A cross section show- 
ing these relations adds interest to the paper. 
During the same year Pierce * mentioned iron mines that were 
being worked in the Pompton mountains of New Jersey, and 
described the rocks of the Highlands as granites and schists. The 
1 Eaton, Amos. An Outline of the Geology of the Highlands, on the 
Hudson River. Am. Jour. Sci., 5 :231-35. 1822. 
2 Vanuxem, Lardner, & Keating, W. H. On the Mineralogy of Franklin, 
in Sussex County, New Jersey. Jour. Acad. Nat. Sci. of Phila., v. 2, pt 1, 
p. 277-88. 1822. 
3 Pierce, James. Geology, Mineralogy, Scenery etc. of the Highlands of 
New York and New Jersey. Am. Jour. Sci., 5:26. 1822. 
