57 



sistent formation in the northern part of the same county. Niai/cra 

 Group. — I'he member of the group found in this regiion, is a soft, massive, 

 buff, sub-crystalline to a bluish-green, shaly, limestone, with a character- 

 istic bed of bluish-green shale several feet thick at the base of the forma- 

 tion. Pleistocene. — The area deeitly covered with glacial drift and having 

 no rock outcrop. 



Triassic to Tertian/, Incluftive. — "The only deposits of these ages 

 known (with the possible exception of the Alerom Sandstone) are some 

 gravels found on certain high ridges in Martin and Perry counties, and 

 possibly elsewhere. These are outside the drift area, and above any known 

 stream deposits of gravel. Taken in connection with the uniformity of 

 elevation reached b.y the highest hills, in the Mansfield sandstone area. 

 the Knobstone area and the Silurian area in the southern part of the 

 State, it has been suggested by Mr. Frank Leverett of the United States 

 Geological Survey, that at least southern Indiana was reduced to base 

 level in Tertiary times. In that case the present and pre-glacial topog- 

 raphy of Indiana would date from some time in the Tertiary. This Ter- 

 tiary erosion might also aceoiuit for the absence of cretaceous deposits, if 

 any such were ever laid down in the State. Until more study shall have 

 been given these gravels and their interpretation, the matter of this para- 

 graph must be considered more as a suggestion than as a demonstrated 

 fact."* (See Report State Geologist 1872, p. 138; 1807, p. 22.) 



The highest point in the State is in the southern part of Randolph 

 County, which at the highest level is about 1,285 feet above sea level. It 

 is on this height of land that both the East and West forks of White River 

 have their source. The C, C, C. & St. L. R. R. (Peoria Div.) passes along 

 this divide between the head waters of these streams. The West Fork 

 inci'eases in volume and velocity more rapidly than the East Fork, which 

 reaches its destination by a very winding course. Its length is greatly in- 

 creased and its slope decreased by its numerous meanders, but it is still a 

 moderately swift stream. After reaching the unglaciated area the direc- 

 tion of the stream is greatl.v influenced by the joint planes in the geological 

 formations. The main streams of these forks grow farther apart until 

 they reach Shelby and Marion comities, where the.v approach each other, 



Note.— For description, composition, structure, extent, uses, etc., of the various for- 

 mations named above, see Thompson, 17th Ann. Rep., pp. 30-40; Hopkins, 20th Ann. Rep., 

 1895, pp. 188-323: Kindle, 29th Ann. Rep., pp. 329-368: Hopkins and Siebenthal 21st Ann. 

 Rep., 1896, pp. 291-427; Blatchley 22d Ann. Rep., 1897, pp. 1-23; Ashley 23d Ann. Rep., 1898; 

 Siebenthal 25th Ann. Rept., 1900, pp. 330-39 ; 30th Ann. Rep., 1901; E. R.Cumings,in Pro. 

 Ind. Academy of Science, 1905, pp. 85-100. 



