230 F. V. Hayden on the Geology of the Country 
ing the active operations of the party he accompanied that part of the 
comn and that was with myself—the geological examinations made by 
the :econd division were under the immediate direction of Dr. C, M.- 
Hin:s of this city. 
It is believed that the final results of the expedition will add largely to 
all lranches of the scientific knowledge of the country. 
W. RAYNOLDS, Capt. Top. Engrs. Comdg.] 
Washington, D. C., Jan. 17th, 1861. : 
B. Dr. Haypen’s SKETCH. 
: 
I. Granite, Stratified Azoic, and Eruptive Rocks,* ” Pe 
i ilurian ae 
* By granite or granitoid, I mean those unstratified crystalline rocks in the West ” 
| m 0 t : 
y stratified series of non-fossiliferous. ‘a a se 
ary between the granite and Potsdam sandstone, y eruptive rocks, thos 
have been melted by volcanic heat and brought he surface in a more 
fluid condition, at various periods, is i ie ag a ET: 
