14 EXPEDITION TO THE 



states of New Jersey, Pennsylvania, Maryland, and Vii - 

 ginia. This formation extends in a general north-easterly 

 direction. The rock appears to be nearly horizontally stra- 

 tified, but from the slight inclination which it presents to 

 the north, the strata are presumed to extend in a north- 

 east and south-west direction. 



The limestone and red sandstone, with its accompanying 

 red slate, alternately appear on the west side of the Sus- 

 quehanna. The limestone is generally found in the val- 

 leys, and the sandstone upon the acclivities of the hills, 

 which are generally crowned with small patches of trap. 

 This rock occurs, however, only upon the higher hills, 

 where it seems to have protected the sandstone from de- 

 composition. 



On approaching Millerstown, the country assumes a 

 more broken appearance ; the limestone ceases, and indica- 

 tions of crystallization are visible in the rocks. Millers- 

 town, (sometimes called Fairfield,) is situated on the east- 

 ern side, and at no great distance of that ridge which is 

 generally called the South mountain, and which may be 

 considered as the easternmost of the parallel ridges, which 

 constitute the great chain of Alleghany mountains, at least 

 in the southern part of Pennsylvania. In the vicinity of 

 this place, there are masses of a calcareous breccia, in every 

 respect similar to that found on the Potomac, and which 

 has acquired of late a well-merited celebrity, on account of 

 its having been used for the beautiful columns which adorn 

 the interior of the Capitol, in the City of Washington. 

 This breccia, which is too well known to require descrip- 

 tion, consists of fragments of limestone of very many kinds, 

 differing in texture, colour, &c. all imbedded in a calcare- 

 ous cement. Some of these fragments have a fine sacca- 

 roidal or subsaccaroidal grain, while others are compact. 



