Geology and Mineralogy. 157 



region having been re-examined. Prof. White deals with the 

 Coal Measures only, of which, in accordance with the Pennsyl- 

 vania classification, he recognizes five groups, beginning with the 

 Pottsville Conglomerate, XII, and ending with the Permo-Carbo- 

 niferous, XVI. Each of these groups is the subject of a chapter, 

 of which the first part gives a large number of measured sections 

 to prove the relations of the group, while the second part de- 

 scribes in detail the variations of the several strata. Much of 

 the material is wholly new, nearly all of that relating to West 

 Virginia being published now for the first time. The gathering 

 together of the salient facts from the Pennsylvania reports was a 

 serious labor, for which we should be deeply grateful. Prof. 

 White has been generous in recognition of his fellow-laborers, 

 sometimes overlooking his own work and assigning credit where 

 no credit is due. J. J. s. 



3. Age of the Plants of the American IVlas. — Mr. Lester F. 

 Ward, in a review of the plants of the American Trias, (Bull. 

 Geol. Soc. Amer., iii, 23, 1891) arrives at the conclusion that pre- 

 sent knowledge fixes the horizon of the formation " at the summit 

 of the Triassic system ;" and also that the beds of Europe, " which 

 seem to be most nearly identical so far as the plants are con- 

 cerned, are those of Lunz in Austria and of Neue Welt near Basle 

 in Switzerland," which are referred " by the best European geolo- 

 gists to the Upper Keuper." 



A paragraph on page 25 of the Bulletin of the Geological 

 Society(page 3 of Mr. Ward's article) needs some correction. It 

 reads : " Second, the New Jersey and Pennsylvania area, extend- 

 ing from the Hudson River to the Potomac. I have not used the 

 term 'Palisade area,' which was employed by Professor Dana, 

 because he makes this to include also the Triassic deposits of 

 Virginia and even to embrace the Richmond coal-field." 



Prof. Dana is not aware that he ever made the Palisade area to 

 include "the Triassic deposits of Virginia " of which there are 

 several, or "even the Richmond Coal-Field." In the last edition of 

 his Manual, on page 404, it is stated that the Palisade area 

 extends from New York to Orange County, Virginia. [The same 

 extension is given it in the colored geological map published in 

 the 5th Annual Report of the U. S. Geological Survey (1885), as 

 well as in earlier maps.] The termination in Orange County is 

 nearly 50 miles northwest of the Richmond area. On the next 

 page the Manual, describing the Triassic areas severally, states 

 again the same limits, and makes the Palisade area No. 4, and 

 the area near Richmond No. 5. The first edition of the Manual 

 (1862) gives the same numbering of the areas and the same 

 limits to the Palisade area. 



4. Chalk and flints at the Solomon Islands. — Prof. Liversidge 

 describes (Australian Association, 1890) chalk from Ulawa Island 

 of the Solomon group, containing Foraminifera, but not so abun- 

 dantly as a similar chalk described by him in 1877, from New 

 Ireland. With the chalk were flints closely resembling those of 



