GEOLOGICAL SOCIETY OF PENNSYLVANIA. 



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reposes the bituminous coal of Chesterfield or Richmond, 

 one of the most remarkable carboniferous deposits in the 

 United States; to the consideration of which we propose 

 to devote the present article. 



In order, however, that the continuity of oar de- 

 scription of this coal field may not be interrupted, it may 

 be here expedient to proceed with the geological notes 

 as to the western side of this region. 



On passing westward, the carboniferous beds are suc- 

 ceeded by sienitic rocks and quartzose schist. Their 

 inclination is only discernible at a few points, where they 

 may be observed dipping to the eastward, that is under 

 the coal basin, at an angle of 20 to 30°. During many 

 miles the face of the country possesses an undulating 

 character, and the primitive stratified rocks being here 

 almost wholly decomposed to the depth of many feet be- 

 low the surface; a thick covering of red tenacious clay 

 is produced, to the no small embarassment and delay of 

 the traveller in these regions. 



Gneiss is next seen to occupy a breadth of two or 

 three miles, dipping to the east as before. Hornblende 

 slate succeeds, followed by talcose slate ; then a gritty 

 iron ore, or coarse ferruginous sand rock, inclining at an 

 increasing angle eastward. Other beds of hornblende 

 slates, passing into granite, appear on approaching 

 Goochland court house, beyond which the surtace is al- 

 ternately striped with red clay, and a sandy or gritty 

 soil, denoting vaguely the corresponding mineral charac- 

 ter of the subjacent rocks. This area is traversed by 

 numerous parallel veins or walls of quartz, whose superior 

 indestructibility has resisted the action of the elements. 

 Hornblende slate is again seen, accompanied by various 

 modifications of rocks containing that mineral. 



This brings us to the western division of our proposed 

 section or diagram, pi. 16, fig. 3, and it only remains 

 further to add that the inclination of the stratified masses, 



