[23] 



106 



quarry were of a pleasant and warm gray. See specimen No. 23. These 

 latter, however, are difficult of access, having several strata of inferior 

 stone over them, and cannot therefore be obtained without great and un- 

 necessary expense, and should only be resorted to in the event that no 

 other stone of equal color and quality can be found in a more favorable 

 position. 



The College quarries lie to the northwest of Bull run and Seneca creek. 

 Tlie dip of the strata is at an inclination of about 20° to the southwest. 



To the northwest of these quarries, and on the same face, are quarries 

 belonging to Mr. Peter, where we found the buff-colored stone; (specimen 

 No. 24.) It is much to be regretted that this stone is neither sufficiently 

 durable, from its being argillaceous, nor found in sufficient quantities for 

 the purposes of the institution, as, in my opinion, it surpasses in color any 

 stone I have as yet seen in this country; resembling in hue that used in 

 Edinburgh, and the Caen and Bath stones, \vhich were so much used and 

 so highly esteemed by the architects of the middle ages. 



To the north of this quarry is one belonging to Mr. Lee. The color of 

 the stone in this is a warm gray, and the texture is fine and highly sili- 

 cious, and the quality is excellent. It is a liver-rock, and is found in^ 

 several strata of considerable thickness, which would afford an abundant 

 supply. Some of the layers, however, contain copper, which might possi- 

 bly render it liable to stain by long exposure, unless carefully selected. 

 See specimen No. 25. 



From this quarry, the most northern one we examined, we proceeded 

 in a southeasterly direction, recrossing the College quarry to the Bull run, 

 belonging to Mr. Peter. The quarry on this run has been opened at a 

 point up the stream, distant about 300 yards east of the Potomac. 



The stone is of excellent quality, of even color, being of a warm gray, 

 a lilac tint resembling that known as ashes of roses, and can, from all 

 indications, be found in sutiicient quantities to supply all the face work for 

 the instituyon. 



There appear to be three layers of this color, which are, respectively, 

 20, 24, and 30 inches in thickness. 



The stone is highly silicious, rings when struck with the hammer, and 

 where it has been exposed in the bed of the Bull run to the action of the 

 water and frost apparently for ages, and in the culvert under the canal for 

 several years, shows little or no signs of decay. 



We traced strata of this color from the present quarries to the mouth of the 

 Bull run, and found it between an overlying layer of a shaly or slaty ar- 

 gillaceous quality, (which is easily decomposed, and must therefore be very 

 carefully avoided,) and a substratum of the dark red-colored stone, (see No. 

 18 of Dr. Owen's report.) We also found stone of the same color and 

 quality in an old quarry, distant about 600 feet south from the mouth of 

 the Bull run; thus rendering a sufficient supply almost' certain. 



The strata lie well for quarrying, having but a slight covering and slo- 

 ping towards (he run, thus enabling it to be quarried without binding, 

 which will render the expense small ; and ihe color is equal to that of any 

 stone we examined, except the buff. In company with Mr. Peter, we 

 next visited a house built of coursed and hammered rubble masonry of 

 stone of this color, in which it had a pleasing and airy effect upon the 

 eye. Mr. Peter's stable is also built of stone of this color, and produces 



