6 



tained during this reconnoissance, it was important to construct 

 what is termed a geological sec/ion or profile, from actual observa- 

 tions made from point to point in one or more lines transverse to the 

 general ranges of the strata ; thus combining In one view, all the 

 most important mineral formations of the state, together with their 

 prevailing order of succession, and their relative inclinations, or the 

 angle in which each inclines to the horizon. The general line of ob- 

 servation selected for this purpose, extends from Hampton Roads to 

 the mouth of Guyandotte. A belt of country of variable breadth, 

 spreading to some distance on cither side of this line, was the more 

 immediate subject of investigation, and furnished the materials from 

 which the geological section appended to the present report was 

 constructed. 



In prosecuting the examinations necessary for this purpose, no 

 one line of observation was rigorously adhered to, but numerous 

 local profiles were first formed, and thence by a reference of them 

 all to the general line already specified, the entire profile was formed, 

 which is now presented. It is, therefore, tendered at this time only 

 as an approximate delineation of a transverse geological section of 

 the state, and as such, though sufficiently accurate for the purposes 

 of occasional reference in the present report, lays no claim to the 

 minute precision of geological profiles constructed from the accurate 

 data of a detailed survey. Several minor belts also transverse to 

 the general ranges of strata, and remote from the former, were like- 

 wise examined, and particular profiles constructed from the data 

 thus obtained. One of these extends In a general direction from 

 the White Sulphur springs, by Covington and Lexington to Bucking- 

 ham courthouse ; a second from Columbia, by Charlottes.Yille. Turk' a 

 and Rhodes' gap, and Harrisonburg, to the North mountain ; and a 

 third embraces a portion of the Potomac. In addition to these 

 transverse lines of observation, several routes have been explored 

 more nearly conforming to the bearing or direction of the strata. 

 One of these extends in a general direction from Halifax, on the 

 Roanoke, to the lower falls of the Potomac, and is nearly coin- 

 cident with the western boundary of the tide water or tertiary 

 section of the state. Another embraces a general view in the 

 longitudinal direction of the valley of Virginia, from the Potomac to 

 the James river, &c. Beside these, many other lines of "observation 

 were examined, some of them embracing a distance of 50 or 60 

 miles, on either side of the general route. Keeping in view the im- 



