374 RevieiDS — Solmes's Carolina Phospate Rocks. 



it is mainly composed of Polythalamia ; numerous fish, remains, and 

 bones and teeth of 'Cetaceans, are also met with in it. On the 

 San tee Eiver another bed of Eocene marl occurs, older than the beds 

 of Ashley and Cooper rivers, and composed principally of shells and 

 corals. The Marl beds attain a thickness of seven hundred feet in 

 the Artesian Well at Charleston. They yield from 65 to 95 per 

 cent, of Carbonate of Lime. Mr. Holmes also describes a " Buhr- 

 stone" or Millstone Grit of Eocene age, originally a maxl bed, which 

 has been subsequently silicified. The silica has been obtained from 

 superincumbent sand beds, and as hot water will dissolve silica 

 largely, he thinks it " not a wild supposition that the waters of the 

 Tertiary sea may have been at one time heated, and thus facilitated 

 the solution of the silica." We should have been glad to see some 

 evidence in support of this statement, although it is indorsed by 

 Professor Tuomey. 



The Phosphate rocks are of Post-Pliocene age, derived, according 

 to Mr. Holmes, from the Eocene Marl-bed, which is the foundation 

 of the whole of the sea-board country of South Carolina. These 

 nodular fragments of Eocene rocks are composed (like the parent 

 rock from which they are derived) entirely of marine remains. 

 Mingled with them are the bones of large land animals, such as the 

 Mammoth, Mastodon, Ehinoceras, Megatherium, and the gigantic 

 reptile Hadrosaurus, etc. 



The author describes the formation of tbese Phosphate beds on a 

 coast-line of shallow water, where irregular and undulating sand- 

 banks rested upon the surface of the great Marl-bed. The surface of 

 this bed where exposed was worn into cavities and holes, indeed, Mr. 

 Holmes remarks, into a coarsely honey-combed surface, from which 

 fragments were continually broken off, rolled, and finally deposited 

 in the hollows and basins below the ocean level. 



A great elevation of the country subsequently ensued, and the 

 basins remained as so many salt-water lakes, having their bottoms 

 covered with a layer of the nodular fragments of Marl-rock. It 

 was after this elevation that the bones and teeth of the Post- 

 Pliocene animals became mixed with the nodules. Then the gigantic 

 quadrupeds " which roamed the Carolina forests, repaired periodically 

 to these Salt-lakes, and during a series of indefinite ages were 

 engaged first sipping brine, then licking salt, and depositing their 

 faecal remains, and ultimately their bones and teeth, in fact their 

 dead bodies, in these great open crawls or pens." 



To account for the 60 per cent, of Phosphate of Lime which these 

 nodules contain, the author devotes but a small space. Their con- 

 version from a Carbonate to a Phosphate he considers to be due to a 

 dissolution of the Carbonate of Lime by water holding Carbonic 

 acid, and the Phosphoric acid was obtained from the animal remains 

 associated with the nodules. 



That the economical part of this work will prove useful we have 

 little doubt ; we are sorry we cannot say so much for the theoretical 

 or purely scientific portion. The work, we ^ should mention, is 

 illustrated with five gorgeous plates. 



