GEOLOGICAL REPORT. 



LOWER SILURIAN. 



The Trenton Limestone underlies a portion of St. Louis, 

 Franklin and Jefferson counties. No valuable ores have as yet 

 been discovered in this formation. It furnishes good lime- 

 stones and marbles for building and ornamental purposes. The 

 soils formed from it are calcareous and durable. 



The Magnesian Limestone Series * occupies a large part of 

 Jefferson, Franklin, and Webster, and nearly or quite all of 

 Gasconade, Crawford, Washington, Maries, Phelps, Pulaski, 

 La Clede, Wright, and Dallas an area of nearly 6,000 square 

 miles within the limits of the Railroad lands. 



This series of ancient deposits is made up of magnesian lime- 

 stones, sandstones and intercalated beds of chert or impure 

 flint. These rocks contain the best building material in the 

 State. Some of the limestones are not surpassed in beauty and 

 durability. Many of them will furnish inexhaustible supplies 

 of beautiful, variegated marbles. A few of the sandy beds are 

 excellent free stone well adapted to architectural purposes ; 

 while others will afford any desirable quantity of pure white 

 sand for cements and glass manufactures. 



These rocks usually exert a good influence upon the soil ; 

 but there are exceptions. Some of the magnesian limestones 

 decompose so rapidly, and supply the soil with so large a por- 

 tion of magnesia as to impair its fertility ; as is evident in many 

 of the glades on the ridges and slopes, where they come to the 

 surface. In a few localities the sandstones render the soil too 

 arenaceous, while in other places the fragments of chert are so 

 abundant as to prevent its use for ordinary cultivation. It 

 should be borne in mind, however, that these apparent defects, 

 when not in very great excess, give the soil a peculiar adapta- 

 tion to one of the most important departments of husbandry, 

 the culture of the grape. And the time is not far distant when 



* The upper part of this series belongs unequivocally to the age of the Cal- 

 ciferous Sandrock; but since our Second Annual Report was published, the 

 evidence that the lower beds are Potsdam Sandstone has been increased by the 

 discovery of the Lingula antiqua of Hall, by Mr. Broadhead, in Moniteau county 



