6 GEOLOGICAL REPORT. 



hydraulic limestone and one or more of good fire-clay. The 

 Coal Measures are represented on the map by the purple. 



The Mountain Limestone underlies nearly all of Newton, 

 Lawrence and Green, the southern part of Jasper, the north of 

 McDonald, Barry and Stone, the south-west of Webster, and 

 portions of St. Louis, Jefferson and St. Charles, and occupies 

 an area of more than 3,000 square miles. The St. Louis, the 

 Archimedes, and the Encrinital Limestones are developed in 

 the East, the Ferruginous Sandstone, the Archimedes and En- 

 crinital * Limestones in the West. 



The Mountain Limestone contains the numerous and exten- 

 sive deposits of lead and zinc in Jasper and Newton ; the ex- 

 tensive beds of iron in Green and Lawrence ; the marbles of St. 

 Louis, and an abundance of good building stones in all the 

 counties above named. It also exerts a good influence upon 

 the soils, rendering them productive and durable. 



It is represented on the map by the blue. 



CHEMUNG GROUP. 



This division is sparingly developed in St. Louis, Webster, 

 Green, Taney, Stone, Lawrence, Newton and McDonald. Al- 

 though this formation is very thin, its three divisions are well 

 defined in some parts of the West, where the denudation of the 

 middle clay beds lias formed the mounds so conspicuous in the 

 prairies of that part of the State. 



These sandy clays often exert an injurious influence upon 

 the soil. No valuable minerals have been found in these rocks, 

 save some copper in the beds of transition between them and 

 the Encrinital Limestone in Lawrence county. It occupies an 

 area of some 160 square miles, and is represented by green on 

 the map. 



* Tliis formation presents some peculiar features in Lawrence county Its 

 lower part is there made up of heavy beds of whitish, porous quartz rock, as 

 indicated by the following section on the Turnback: 

 No. 1 5 feet of Ferruginous Sandstone. 



" 2 30 feet Encrinital Limestone, with its usual characters. 



" 3 70 feet of brownish gray, porous and hard silicious rock or quartzite. 



" 4 5 feet of soft brown impure Sandstone, with masses of calcareous spar. 



" 5 10 feet of coarse, impure crystalline Limestone ; contains Spiriftr Mario- 

 nensis Chemung. 



" 620 feet of silicious rock like No. 3. 



