1857.] An Exjilanation — Geology of Ohio. 253 



losoplier lias prevented the execution of the contemplated labors. — 

 Allow me then Mr. Editor, while announcing the suspension of the 

 contemplated enterprise, to present a single section, from the mater- 

 ials prepared, as affording to the agriculturist some idea of the in- 

 terest he has in the prosecution of a Greological survey of the State. 

 The descriptions of the mineral regions would, of course, be more 

 minute in detail, and give the exact position of the veins of coal 

 and iron. D. C. 



JUNCTION RAILROAD— CAPACITY OF FERTILE LANDS TO SUSTAIN POP- 

 ULATION—CINCINNATI, HAMILTON & DAl'TON RAILROAD AND ITS 

 CONNECTIONS. 



BY DAVID CHRISTY, CINCINNATI. 



A residence of near twenty years at Oxford afforded the writer 

 ample opportunities of studying the geology of the route of the 

 Junction Railroad, which extends from Hamilton, through Oxford, 

 to Indianapolis. It seems most natural, therefore, for me to take 

 up this railroad first, and, in connection with it, to notice the other 

 branches and connections of that great Trunk Road, the Cincinnati, 

 Hamilton & Dayton Railroad. 



Before proceeding to details, it may be well to offer a remark or 

 two on the connection between the geology of any given section of 

 country and its agricultural capacity. 



What more do you wish to know of a neighborhood, it may be 

 asked, than that its lands are fertile, and capable of supporting a 

 large population, and supplying abundant products for transport? 

 To this question it need only be said, that productive lands do not 

 always retain their fertility. Cultivated lands undergo a process of 

 exhaustion, and become less productive, except care be taken to 

 prevent such a result. This diminution of fertility may be due to 

 one of three causes, or to all combined. Let me explain: 



All soils have been derived from the decomposition of rocks. — 

 Productive soils contain two classes of elements which enter into 

 the combination of vegetation during the process of its growth. 

 Chemists designate these elements by the terms organic and inor- 

 ganic. The organic elements are derived from the atmosphere, and 

 from decomposing animal and vegetable substances; the inorganic 

 elements are all to be found in the jjrimarg rocks constituting the 

 mineral substances of which they are composed. By the decompo- 

 sition and disintegration of this class of rocks, these elements have 



