Dr. J. L. Smith on the Marl from Ashley River. 101 



consequence ; sufficient is it for us to know, that it has an or- 

 ganic origin, having been a part of either moUusca or vertebrated 

 animals, and were it necessary to suppose that it could have ex- 

 isted in only one of these, I should unhesitatingly attribute its 

 origin to the vertebrated animals, particularly on account of their 

 abundant provision of phosphates. Bones were also examined 

 that contained fluorine, when the deposit from which they were 

 taken showed no traces of this element. 



Dr. Daubeny has lately examined the question of the existence 

 of fluorine in recent bones, and decided it in the aflirmative. 



It is not surprising that we should find the phosphates and fluo- 

 rides associated in the animal kingdom, for in the mineral king- 

 dom fluorine is a very common attendant upon the phosphates, 

 as for instance in the Apatites, Wagnerite, Wavellite, Urinite, &c., 

 and I think if we search the mineral kingdom we shall not find 

 so constant an association of any two elements as fluorine and 

 phosphorus. All the phosphates of the alkalies and earths con- 

 tain fluorine. 



If then this element is associated with the phosphates, they 

 must exist together in the soils arising from the disintegration of 

 the rocks containing these minerals, and the plants growing upon 

 these soils would upon taking up the phosphates naturally appro- 

 priate the accompanying fluorides, which two classes of salts 

 would subsequently pass to the same portion of the animal feed- 

 ing upon these plants, namely, to the bones. 



The reason why the existence of fluorine in recent bones is 

 doubtful, may be owing to the fact, that the great mass of the 

 phosphate of lime originally in the soil has from various causes 

 disappeared, and with it the fluoride of calcium ; and that the 

 portion of this latter still remaining is so small, that notwithstand- 

 ing the double condensation that it undergoes through the agen- 

 cy of plants and animals, it is not in sufficient quantity to come 

 readily within the reach of our tests. 



III. Composition of the Marl from Ashley River, S. C. 



The epoch to which this formation of marl is referable, is not 

 yet fully decided, but it probably consists of beds of difierent 

 ages, the newest being as old as the eocene of Virginia and Ma- 

 ryland. It has been explored to the depth of 309 feet in boring 

 a well. Specimens from depths varying from 110 to 309 feet, 



