454 Bibliography. 



more recent deposits. The value, therefore, of these minute medals of 

 creation in the determination of the age of strata is fully established. 



Upon this point D'Orbigny remarks, " that after having devoted 

 twenty years to the study of the Foraminifers he has become fully con- 

 vinced that they can in all cases be used to determine with certainty 

 the age of a geological formation, if in their comparison there is used 

 that precision of observation which is indispensable to every conscien- 

 tious labor in zoology or comparative anatomy." Even where it may 

 be the easiest method to determine the age of a stratum by means of 

 the mollusks and other large fossils which it may contain, the accom- 

 panying microscopic forms, which in general are far more numerous, 

 should not be neglected. The business of the geologist is not merely 

 to identify strata, but to give a comprehensive and philosophical view 

 of all the phenomena of the epoch under examination, and surely none 

 can be more wonderful than those connected with the labors of those 

 Lilliputian chemists, who little by little have separated from the ocean 

 waters, organized masses of carbonate of lime or silica, which play no 

 inconsiderable part in the formation of our present continents. 



In our American strata the Foraminifera are very abundant ; the 

 borings of every Artesian well made through the cretaceous or tertiary 

 strata of the southern states, afford a rich supply of these elegant forms. 

 Beautiful living species occur along our coast, but are rare along our 

 sandy shores, in comparison with the immense profusion in which they 

 occur near the Gulf Stream. From a recent examination of soundings 

 taken at depths of about 100 fathoms and at various points near the 

 Gulf Stream,* it appears that the Foraminifers form along the course 

 of this ocean current a perfect milky-way of organic life, whose nebulae 

 however are easily resolved by the microscope. 



While we close this article by recommending the various works by 

 M. d'Orbigny as indispensable to all who would pursue this branch ot 

 microscopic paleontology, we would also invite attention to an interest- 

 ing memoir by Dr. Mantell, on the Fossil Remains of the soft parts ot 

 Foraminifera in English Chalk and Flint,f and to another by VV. C. 

 Williamson, Esq., on some of the Microscopical Objects found in the 

 Mud of the Levant.^ Both of these memoirs are valuable contributions 

 to our knowledge of the minute workers in lime and silica, and other 

 vast additions may be hoped for in Ehrenberg's long expected volume, 

 which is to give the results of his comparison of the microscopic beings, 

 recent and fossil of all parts of the world. J- W. E>. 



4. Lexicon Scientiarum — a Dictionary of Terms used in the vari- 

 ous branches of Anatomy, Astronomy, Botany, Geology, Geometry, 

 Hygiene, Mineralogy, Natural Philosophy, Physiology, Zoology, Sf c --> 

 for the use of all who read or study in College, School, or Private Life. 

 By Henry McMurtrie, M.D., &c, Prof, of Anatomy, Physiology and 



For these soundings we are indebted to A. D. Bache, Esq., Superintendant o 



the U. S. Coast survey. The soundings abound in many new and interesting or 

 ganic forms, a memoir upon which is now in the course of preparation. 



t Phil. Trans., Part IV. 1846. , m 



t On some of the Microscopic Objects in the Mud of the Levant, and °V^*7®* 

 posits, witii remarks on the mode of formation of Calcareous and Infusorial =>i 

 ceous Rocks, by Wm. C. Williamson, Esq. Manchester, 1847. 



