404 Scientific Intelligence. 



from the north, a diamond-bed is not likely to exist in the imme- 

 diate vicinity, -but is rather to be looked for in the direction from 

 which the drift came. The diamond is a rhombic dodecahedron, 

 deeply pitted with circular, elongated, reniform markings. In 

 color it is slightly grayish-green. It is one of the kind of dia- 

 monds, however, of which the color is likely to be superficial, and 

 it would probably cut into a rounded stone. Its weight is three 

 and three-quarters and one-sixteenth (3f ^) karats. This is the 

 second authentic occurrence of diamond in Oregon, Wis., the 

 other occurrence being that of three small stones, the largest of 

 which weighed (ff) twenty-five thirty-seconds of a karat. A 16- 

 karat diamond was reported to have been found, also in the glacial 

 drift at Waukesha, Wis., in 1884. Some litigation resulted from 

 its finding, and considerable doubt was expressed at the time as 

 to the genuineness of the discovery. 



5. Les Enclaves des Roches Vblcanique ; by A. Lackoix (Ann. 

 dePAcad. de Macon. Tome X, 1893, pp. 710). — Nothing per- 

 haps marks more clearly the great advance that is being made in 

 the science of petrology than the appearance of a handbook like 

 this, devoted to a special phase of the subject. The inclusions 

 occurring in volcanic rocks have been previously studied by Pro- 

 fessor Lacroix (Bull, de la Soc. Geol. de France, vol. xviii, p. 845, 

 1890), but in the present memoir he has greatly extended his own 

 work and adds a resume of the observations of others. Accord- 

 ing to his method of classification the inclusions are divided into 

 two classes, those whose origin is known or supposed to be not 

 the same as that of the rock in which they occur, as a fragment 

 of schist in basalt, which are called enallogenetic (enallogene), 

 and those whose origin is inferred to be similar, as sanidinite in 

 phonolites and trachytes. These are called homogenetic. The 

 volcanic rocks, for classificatory purposes, are also divided into 

 two classes, the basaltic ones, those of dark color, basic in compo- 

 sition, and which have been reproduced artificially, and trachytic 

 rocks, chiefly feldspathic, which have not yet been made by artifi- 

 cial processes. It is evident that the study of inclusions of the 

 first class is that of extreme contact metamorphism. Many 

 interesting results and theories are given which it would be im- 

 possible to discuss here. The volume is well illustrated by a large 

 number of cuts and beautiful colored plates. It will prove of great 

 service to all working petrographers. l. v. p. 



6. The Laramie and the overlying Livingston Formation in 

 Montana, by Walter Harvey Weed, with Report on Flora, 

 by Frank Hall Enowlton, (Bull. U. S. Geol. Survey, No. 106.) 

 pp. 6S, 6 pi. 1893. — The authors of these papers have given val- 

 uable descriptions of the geology and of some of the fossil plants 

 from the rocks studied in the region along the base of the moun- 

 tains south of the Yellowstone, near Livingston, Montana. 

 The total section in the vicinity of Livingston and in the canyon 

 of the Yellowstone consists of Algonkian schists at the base ; 835 

 feet Cambrian shale, limestones, with some quartzites at the base ; 



