260 



witness few traces of the changes noticed in the materials of the 

 mass above. The quantity of oxide of iron in the free state 

 mixed with the marl causes it to be rather hard to dig; this is 

 the case with nearly all the more ferruginous kinds, but a brief 

 exposure to the air renders it friable, when it is found to be a 

 very powerfully fertilizing marl. Striking benefits result from 

 the use of this marl when it is applied in the ratio of about ten 

 loads to the acre. In this bed have been found teeth of the 

 mosasaurus and several bones apparently of the fossil crocodile. 

 Mr. Lawrence states that his lower or dark green marl, which is 

 very full of the astringent matter or sulphate of iron, will not 

 admit of being lavishly employed, for it then invariably poisons 

 the crop. If as much as twenty-five loads be used, the growth of 

 the corn is seriously checked ; nor does it recruit until late in the 

 season, after which the vegetation is wonderfully quickened. The 

 upper stratum, on the other hand, will admit of being applied in 

 any excess, one hundred loads or even more, producing no dele- 

 terious effects upon the crop. Where the banks of the meadows 

 are high, a different stratum from either of the previous two is 

 seen, and to all appearance occupying a higher place in the 

 series. This is the calcareous sandy stratum which in another 

 part of this Report I alluded to as being in all probability a 

 deposit of the same date with the limestone of Vincentown and 

 Mannington. It is here a yellow calcareous sand with scattered 

 grains of marl, and with a multitude of solid casts of various 

 fossils, some of which do not show themselves in the green marl 

 beneath. In this bed I have procured copro/ites.* All the casts 

 in question consist chiefly of carbonate of lime in an earthy state 

 mixed with a little clay and sand. 



The stratum in some places is more than twenty feet in thick- 

 ness. Being the upper bed, it is in many instances the only 

 accessible one, in which case I think it deserves to be employed 

 as a substitute for marl, not merely for the amount of calca- 

 reous matter in it, but for the quantity of the greensand. Bones 

 of some reptile, the crocodile apparently, are found in this stratum, 

 and we may hence form a conjecture of the source of the copro- 

 lites. From the same bed we may procure solid internal casts 



• Coprolites, are the fossilized dung of extinct animals. 



