Geology and Mineralogy. 257 



metamorphic limestone of Hillsdale, from among my collections 

 in the region, and finds, on slicing it, besides indistinct impres- 

 sions of shells, a small Gasteropod, probably a Maclurea related 

 to M. crenulata, though in some respects different from that 

 species. It appears to indicate that the beds are Calciferous. 

 The Millerton fossils, already described by Prof. Dwigbt, are in 

 the same limestone belt, but nearly twenty miles farther south, 

 Hillsdale being situated over the northern end of the belt. 



J. D. D. 



6. Revision of the Genus Araucarioxylon of Kraus, with 

 compiled descriptions and partial synonymy of the species / by 

 F. H. Knowlton. Proc. U. S. Nat. Mus., vol. xii, 1889, pp. 

 601-617. Also separate, No. 784, Washington, 1890. — Professor 

 Knowlton has done a useful service in clearing up this knotty 

 subject, which is much broader than the title indicates, since it 

 includes the eleven species of Cordaites founded on internal struc- 

 ture, and twenty-six species of Dadoxylon, all of which are Paleo- 

 zoic, but are shown to possess the araucarian type of structure 

 and therefore to have probably been the direct ancestors of the 

 thirteen species of Araucarioxylon from the Mesozoic and Ceno- 

 zoic. The one Tertiary species of this last genus (A. Dceringii 

 Conwentz) is of special interest as coming from South America 

 where the genus Araucaria is native, thus seeming to complete 

 the connection of a type of plants that began in the Silurian and 

 still persists. Of Araucarioxylon ~Virginianum (p. 615) it should 

 be said that the apparent anomaly of finding a species of that 

 genus in the Potomac formation, characterized by the sequoian 

 type Cupressinoxylon, has recently been cleared up by the dis- 

 covery that the fossil wood found at Taylorsville, Virginia, occurs 

 in a modern deposit (probably the Appomattox formation) imme- 

 diately overlying the Older Mesozoic or Triassic (Rhetic or Keu- 

 per) from which its materials are taken, and to which the fossil 

 wood rightly belongs. l. f. w. 



7. JJeber dei Reste eines JBrotfruchtbaums, Artocarpus Dick- 

 soni n. sp., aus den Cenomanen Kreideablagerungen Grbnlands ; 

 von A. G. Nathoest. Kongl. Svenska Vetenskaps-Akademiens 

 Handlingar, Bd. xxiv, pp. 1-10, 4°, pi. i. Separate, Stockholm, 

 1890. — The large-lobed leaf figured here is believed by the author 

 to represent an Artocarpus of the type of the bread-fruit tree, A 

 incisa, but the details of nervation are wanting. The fruits asso- 

 ciated with it, as well as that from Oeningen which Heer called 

 A. Oeninge?isis, and of which Nathorst here gives a new figure, 

 appear without doubt to belong to the fig family, and if they are 

 not small bread-fruits they are probably true figs. There is no 

 present objection to regarding this leaf as that of Ficus. Nathorst 

 shows that it resembles several that have been found in American 

 deposits and referred to Aralia, Myrica, etc., and Lesquereux in a 

 work not yet published, figured similar ones from the Dakota 

 group under the names Liriodendron, Sterculia, etc. l. f. w. 



8. Tertiare Pflanzen der Jnsel Neusibirien / von J. Schmal- 

 sets. Mem. Acad. Imp. Sci. de St. Petersburg, 7 e serie, tome 



