350 



tendency they have to concrete, and give origin to those 

 large quantities of bog ore which have hitherto proved so 

 great a source of profit to the possessors of the land. In 

 this way, the formation of this ore may be considered as 

 of daily continuance, and consequently on the increase. 

 A few years since, this iron was shipped in large quanti- 

 ties to the city of Philadelphia for stove castings, and for 

 the purpose its quality most admirably adapts it. 



Beds of shell marl, either covered or surrounded by 

 margins of peat, are not unfrequently to be met with in 

 the marshy depressions of this plain ; both of which sub- 

 stances, when judiciously used as manures, have proved 

 of essential service to some of the lands in the vicinity; 

 but at other limes they have been the source of some con- 

 siderable evil, merely in consequence of the absence of a 

 little chemical knowledge of the nature of the soils upon 

 which they were improperly introduced. 



The rains that descend and percolate these yellow sands, 

 are, in many instances, immediately thrown oiF by the 

 sloping surfaces of the impervious clays beneath, and 

 again make their appearance in the form of copious springs 

 among the various depressions scattered over the surface 

 of the plain. From these springs, the numerous minor 

 streams that ramify the country derive their origin. But 

 many of these waters find their way into basins or reser- 

 voirs at the bottom of the torn out trenches and disrup- 

 tured portions of the clay, from whence our farmers most 

 generally obtain their supplies ; and they consider them- 

 selves extremely fortunate when, in digging their wells, 

 they at the first attempt succeed in reaching one of these 

 repositories. In these researches for water, they are al- 

 most altogether guided by chance, and oft times wonder 

 that their labors are attended with such ill success. The 

 accompanying diagram is taken from an actual section at 

 one of the many excavations made in the neighborhood of 

 our city, and will in a great measure aid in illustrating 



