REPORTS OF THE BUILDING COMMITTEE, 613 



and perishable a nature, and which have been exposed for 20 years to the action of 

 running water and alternate thawing and freezing, which exhibit little or no altera- 

 tion, except that they have become so indurated that they turn the edge of the chisel, 

 and are a little dingy on the surface. 



Mr. Peter, on whose property this quarry is situated, has built a fine barn of these 

 freestones. He assures me that there are stones in that barn 50 years old, which have 

 been in three buildings. On one corner-stone, where the figures " 1824 " had been cut 

 in that year by the point of a penknife, the rock now is so hard that it would soon turn 

 the edge of a well-tempered tool. 



Interstratified with these grit-stones are some argillaceous, marly-looking beds, 

 (No. 20,) especially prevalent towards the upper outcrop of the stratified mass con- 

 stituting these hills. These layers are, of course, entirely unfit for any kind of 

 building purposes. The sandstone beds differ very much, not only in color, but also 

 in hardness and texture. Some are fine-grained, aDd can be wrought to a sharp arris; 

 others are coarse-grained, and even assume the character of a conglomerate ; these 

 latter, of course, are entirely unfit for the finer purposes of architecture. Amongst 

 a series varying so much, not only in color, but in texture and composition, a careful 

 selection becomes a matter of the utmost importance. 



About a quarter of a mile further west, in a bold escarpment of 20 or 30 feet in 

 height, close to the margin of the canal, is the " College quarry." Here the strata 

 assume a somewhat different character. Above, they are of a crumbling, argillaceous, 

 marly nature, producing a retentive soil, well adapted for the growth of wheat and 

 corn ; beneath these disintegrating beds are red and rather argillaceous freestones of 

 and inferior quality, which pass downwards into light greenish-gray beds, varying 

 from a foot to two or two and a half feet in thickness. 



At about fifteen feet from the top is the most important bed exposed in the quarry, 

 of a greenish-gray hue, usually called the " dove-colored bed ;" see specimen No. 21. 

 Beneath this, as far as can be ascertained from the rubbish strewed over the lower 

 face of the quarry, are brown and bluish-purple beds, (No. 22,) of inferior quality. 

 Here, as at Bull run, the strata dip to the west at an angle of about 15° or 20° ; so 

 that the middle layers crop out towards the summit of the hill. Near the top the 

 dove-colored bed is two feet thick. Sixty feet down the slope of dip it has increased 

 to four feet ; forty-five feet more, it is six feet ; and fifty-four feet more, it is nine feet 

 thick. At the same rate of increase to the west, beyond where it is exposed to near 

 the level of the canal, it would be twelve to thirteen feet. The color of this bed is 

 rather cold, but it is much admired by some persons. It is faintly striped parallel to 

 the stratification, (see 21a); it has also some small faint spots, or "pock," as the 

 stone-masons call it, (see 21a), not quite so hard as the body of the rock. This 

 stratum is not near so easily worked as the best beds in Bull run quarry ; indeed it is 

 harder to work than marble. If this dove-colored bed is worked extensively, there 

 will be considerable expense incurred in stripping, since there are fifteen feet of solid 

 strata overlaying it. 



A few hundred yards west of this is another quarry, equally bold, and composed of 

 similar beds, their tints being for the most part gray, greenish-gray, and dove- 

 colored. 



Beyond this, along the canal, the ground is flat and wet, and the hills recede 

 towards the north, so that to the west of the last described quarry, for fifteen or 

 twenty miles, building-material cannot be procured so convenient to navigation. 



Between the College quarry and Bull run there are several localities close to the 

 canal, where some rock has been quarried. The beds exposed are of warm red tints, 

 similar to the red sandstones in Bull run. At these quarries, and in Bull run, the 

 material for the construction of the aqueduct and locks in this part of the Ohio and 

 Chesapeake canal were obtained. These works have stood the test of time as well, if 

 not better, than any of the other structures along the whole line of this improvement. 



The investigations in the vicinity of Seneca creek prove conclusively that the bluffs 

 on the banks of the canals, for about three-quarters of a mile, afford abundance of 

 freestone for building purposes, equal and even superior to those which are obtained 

 in the quarries of New Jersey, which supply the New York market. 



If this freestone should ultimately become the choice of the Building Committee of 

 the Smithsonian Institution, a very careful selection will be necessary not only as 

 regards the particular color preferred, but that it be those softer varieties of pure 

 grit stone, free from all argillaceous or marly admixture, and containing none of 

 those "pock" marks, or small spots and cavities, which not only injure its appear- 

 ance, but detract from its otherwise durable nature. They must also, to insure dura- 

 bility, be in all cases laid on the bed as in the natural position in the quarry. 



