106 NORTH-CAROLINA GEOLOGICAL SURVEY. 



follows necessarily, from the manner in which these marls 

 have accumulated, that they should vary in composition, and 

 that the substance which reduces the quantity of carbonate 

 of lime, should be sand. 



A ready method by which its quantity may be estimated 

 is by washing a given quantity. It will be seen, that by agi 

 tating it in a vessel of water, there is a considerable quantity 

 of fine, inpalpable white powder. Wash it until the water 

 pours off clear, and the sand with the coarse fragments of 

 fossils remain. The existence of much sand is not suspected 

 at first, but as washing progresses, it will be found to prevail, 

 in some cases, over the carbonate of lime. 



77. Upon the Neuse, about twenty miles above ISTew- 

 bern, heavy banks of the marl under notice occur, which 

 extend continuously for more than a mile. This exposure of 

 marl is upon the plantations of Samuel Biddle and Benjamin 

 Biddle. It is accessible, and forms steep escarpments on the 

 south side of the river. On account of the accessibility of 

 this outcrop of marl, it will hereafter become an important 

 deposit from the lime w r hich it is capable of furnishing. It 

 is consolidated, and may be quarried for the kiln, but it also 

 furnishes an abundance of marl in a fine state of subdivision. 



It has been tried imperfectly as a fertilizer, but while the 

 result w r as disastrous, we may infer from it, that it possesses 

 as valuable properties as the kind used by Mr. Wadsworth, 

 which has been described already. The quantity used by 

 Mr. Biddle, in his first experiment, was 600 bushels to the 

 acre ; consequently, most of the vegetation was killed, and 

 very little has grown upon the land, thus excessively marled, 

 for six years. It is just recovering from the dose. The con 

 solidated part of this outcrop of marl contains : 



Sand, 20.00 



Carbonate of lime, . . 78.60 



Oxide of iron and allumina, 1.70 



100.30 



