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crop of the white calcareous rock in question Hes at the base of a liill on 

 Hook's run, about twenty to twenty-five feet high, and pitches at an an- 

 gle of some forty five degrees into the base of the hill, which is here on 

 a level with the bed of Hook's run, at the same time inclining to the west 

 so that it is inaccessible except at great expense of labor. 



There is a sonrewhat better exposure of the Hook's rvm marble at a lit- 

 tle higher level, on a hill a few hundred yards to the south; and here the 

 best specimens were procured; see No. 15. Part of the ledge is com- 

 posed of white calcareous layers, which are said to be susceptible of a 

 pohsh. The rock at both places has a ragged, irregular, and uneven 

 fracture, and is so interspersed with white and green talc, that it cannot be 

 considered of much value as a building-material. It is possible that be- 

 neath this a purer and better rock might be reached; but the surface indi- 

 cations do not even favor that conclusion. Unless the bed should be brought 

 to the surface by an upward turn of the contorted strata on the south side 

 of this range of hills, there is no possibility of getting at it. Mr. Mc- 

 Glauchren intends to try, if possible, to open a quarry, with a view to 

 ascertain more satisfactorily the extent and quality of this material. 



On the whole, in its present situation, this marble seems worthless for 

 the present purpose. 



During the examination of structures and monuments of Baltimore 

 marble, both in Green Mount cemetery and in the city of Baltmiore, with 

 a view to ascertain the durability and facility of working this material, I 

 was so much struck with the beauty of some of the granite vaults and 

 fronts of buildings that I determined to visit the quarries from whence 

 this material was procured, more especially as the owner, Mr. Green, in- 

 formed me that he v/as confident he could furnish it at a cheaper rate than 

 the white marble could possibly be supplied, and as it was only two miles 

 out of my way in returning from the Point of Rocks. 



Accordingly, I stopped at Woodstock, 1(3 miles beyond the Relay House, 

 and inspected carefuhy the Watervdle branch and the Fox rock quarries in 

 this vicinity; both of which are well opened, and aftbrd a good oppor- 

 tunity of judging the quality and extent of this formation. 



For about a mile square at this locality is an outburst of quartzose granite 

 of magnificent quality, both as regards beauty of appearance, compact- 

 ness of structure, and uniformity of color, texture, and composition. I 

 have never seen anything superior in this country; indeed, I doubt whether 

 it can be excelled in any country. The proportion of felspar and mica is 

 very sniall. The former is only in minute specks, the latter in small black 

 scales, whilst the great bulk of the rock is a vitreous quartz. 



In consequence of the mica being only in small regular disseminated 

 flakes, it imparts to the rock an agreeable light gray, well adapted, in my 

 judgment, to the Norman style of architecture. 



In consequence of the composition and texture of this granite, it must 

 possess a durability not to be surpassed by any building-material. For 

 the same reason, it must be difficult and expensive to cut; but in conse- 

 quence of the precision with which it splits, not only in the lines of 

 cleavage, but even across the grain, it may possibly be furnished in com- 

 petition with marble. 



To give some idea of the remarkable facility with which the granite in 

 question cleaves, I may state the following facts, which came under my 

 observation: A slab twenty feet long and one foot square was split longi- 

 tudinally into two, nearly as accurately as if it had been sawed. 



