104 



THE FERN BULLETIN 



The temperature as averaged from readings of four- 

 teen years ranges between 49.9° Fahrenheit in the nor- 

 thern part of the State, 51.6° in the central and 54.2° 

 in the southern. The average annual precipitation for 

 the whole State as based on readings for ten years is 

 38.8 inches, being somewhat less than the average in 

 the northern, and somewhat more than the average in 

 the southern part of the State. 



The geology of the State is rather simple. Strata 

 of Ordivician, Silurian, Devonian, Mississippian, Penn- 

 sylvanian, Pleistocene, and recent age outcrop in the 

 state. The strike is slightly west of north and the dip, 

 averaging 20 to 25 feet per mile, is to the south of west 

 owing to the Cincinnati uplift. Thus the oldest forma- 

 tion, the Trenton, outcrops in the extreme southeast 

 corner of the State. The Ordivician, Silurian and De- 

 vonian rocks are largely limestones and shales, the 

 lower Mississippian strata (Knobstone group) are 

 largely shales and sandstones capped by the overlying 

 Mississippian limestones, the thickest in the State. The 

 latter are overlain by the Chester and Pennsylvanian, 

 chiefly sandstone and shale. Folds and faults are al- 

 most entirely absent. Outcrops of the foregoing are 

 largely confined to the southern part of the State, as 

 the northern two-thirds is covered by the drift sheets 

 of the Pleistocene. 



"The topography * of Indiana is somewhat diversi- 

 fied. The northern part of the State is covered by ice 

 plains, which are characterized by many lakes and 

 swamp areas, with sluggish streams and no deep valleys 

 or high hills, the broad plain being diversified only by 

 the inequalities of the glacial deposits. These features 

 characterize, in the main, the northern third of the 

 State. 



* Hopkins, T. C, A short description of the Topography of Indiana: 2*th Ann. 

 Rept. Ind. Dept. Geology and Nat. R»p. 1903. 



