June 5, 1SS5.1 



SCIENCE. 



469 



Id the Bridger formation, Professor Cope has 

 not achieved such great things as in the earlier 

 periods. Nevertheless, the sections on the 

 reptiles, the rodents, and the tapiroids Hyra- 

 ckyus and Triplopus, are notable contributions 

 to the subject. 



In closing this very brief and inadequate 

 sketch, we must call attention to the beautiful 

 series of miocene carnivores with which part i. 

 ends. Nothing can exceed the perfection of 

 their preservation, and they enable the paleon- 

 tologist to follow the evolution of the group 

 without difficulty. Professor Cope says with 

 much truth, " No fuller genealogical series 

 exists than that which I have discovered 

 among the extinct cats." 



As is unavoidable in the case of a volume 

 nearly five years in course of printing, this 

 book contains much that riper judgment and 

 fuller knowledge have modified. Thus have 

 arisen the occasional contradictions between 

 different parts of the book ; and in recent 

 articles in the American naturalist the au- 

 thor has expanded and modified many of his 

 conclusions. But, aside from these, some of 

 his results are open to serious question, and 

 with scarcely any of his phylogenetic tables 

 can we fully agree. His tendency seems to 

 be to generalize too hastily from the study of 

 some special structures, as the dentition or the 

 feet, to the exclusion of other important parts. 

 The book has been rather carelessly printed, 

 and shows man}- typographical errors ; and the 

 references to the plates are frequently and 

 annoyingly wrong, compelling the reader to 

 a tedious search. The plates themselves can- 

 not be praised : many of the figures are badly 

 drawn, and in one case, at least, the drawing 

 is ludicrous (woodcut, fig. 25a). With few 

 exceptions, the lithographic work is not up to 

 the usual standard of the Sinclairs, and con- 

 trasts unfavorably with the exquisite work- 

 manship of Professor Marsh's volumes. 



But, in spite of these drawbacks, Professor 

 Cope has done a grand work, which is an or- 

 nament to American paleontology, and must 

 ever remain a landmark in the history of the 

 science, as well as " a monument to the labor 

 and genius of its author." 



PHILLIPS'S ORE-DEPOSITS. 



Considering the immense importance of the 

 mining industries, it is remarkable that there 

 have been so few treatises on the manner of 



A treatise on ore-deposits. By J. Arthur Phillips, F.R.S. 

 London, Macmillan & Co., 1884. 



occurrence and origin of the various ore- 

 deposits. 



With two or three noteworthy exceptions in 

 German} T , and one or two in France, the liter- 

 ature on this subject is confined to the vast 

 number of special papers. Whitney's ' Metal- 

 lic wealth of the United States,' a model work 

 which has been of great usefulness, treated, in 

 its descriptive part, only of our own country. 

 Mr. Prime's translation of von Cotta's ' Erz- 

 lagerstaettenlehre ' has been for years the only 

 general work on the subject in the English 

 language. Since that was written, our mani- 

 fold mining industries have assumed an im- 

 portance that will be best understood when we 

 say that during the year 1880 there were nearly 

 ten thousand mines of all kinds and sizes 

 operating east of the 110th meridian. This 

 does not take into account the mines of 

 the precious and other metals of the west, 

 which must number over three thousand. 

 There is a pressing need of a general work 

 based on a survey of our own rich field. 



Pending the appearance of such a work, this 

 book by Mr. Phillips, who has visited many 

 American mines, draws largely, both for facts 

 and theory, from the American experience of 

 its author, and will be found to be very ser- 

 viceable. 



In its general plan and appearance it recalls 

 von Cotta's work. The first hundred pages 

 are devoted to the general classification of 

 deposits. The remaining five hundred or 

 more pages describe in detail the noteworthy 

 and instructive occurrences throughout the 

 world. 



The classification adopted is well chosen, 

 and is as simple as is consistent with our 

 knowledge of the subject. 



I b 



Deposits formed by the mechanical ac- 

 tion of water. 

 Deposits resulting from chemical action. 



a. Deposits constituting the bulk of metal- 



liferous beds formed by precipitation 

 from aqueous solutions. 



b. Beds originally deposited from solution, 



but subsequently altered by rneta- 

 morphism. 



c. Ores disseminated through sedimentary 



beds in which tbey have been chem- 

 ically deposited. 



a. True veins. 



b. Segregated veins. 



c. Gash veins. 



d. Impregnations. 



e. Stock-works. 

 /. Fahlbands. 



g. Contact deposits. 



h. Chambers, or pockets. 



In the general part, which follows, these 

 different forms are discussed in the light of the 

 latest investigations. 



The forming of the siliceous gangue in fis- 

 sures by lateral secretions is illustrated in the 



I. Superficial. 



II. Stratified. 



III. Unstratified. 



