Geology and Natural History. 105 



elementary principle of Physiography, and Professor Hall has 

 done his state a service in calling attention to its wealth of 

 natural scenery. Explanations of the peculiar drainage systems 

 and numerous lakes are particularly interesting. 



6. Plumasite, an oUgoclase-coriindum rock near Spanish Peak, 

 Cal.\ by A. C. Lawsois". Bull. Geol. Dept. Univ. Cal., vol. 3, 

 No. 8, 1903, pp. 219-229. — The author comments on discoveries 

 made during recent years, which show that corundum is a not 

 uncommon constituent of igneous rocks, and then describes an 

 occurrence in which it is an essential constituent of the rock of a 

 dike cutting a belt of peridotite on the lower east flank of Spanish 

 Peak in the Sierra Nevada. The dike is about 15 feet wide com- 

 posed of a white rock made up of feldspar, which varies from 

 coarse to fine and which was determined to be oligoclase. In 

 places this is found to carry considerable corundum in imperfectly 

 formed violet-blue crystals. In the specimens examined the 

 corundum made up 16 per cent of the rock, the remainder being 

 oligoclase. For this type the name of plunriasite is proposed 

 from Plumas Co., Cal., in which it occurs. 



An investigation of the peridotite was made and the results of 

 this are also given. l. v. p. 



7. An Experimental Garden in Cuba. — Three years ago, Mr. 

 E. F. Atkins, of Boston, who has extensive interests in Cuba, 

 placed at the disposal of the Botanic Garden of Harvard Uni- 

 versity such land, labor, materials, and money, as might be 

 required for a small experimental station for the study of certain 

 tropical plants in their economic relations, especially with the 

 view to improvement in their yield and quality. Arrangements 

 were completed by which the more important tropical plants 

 adapted to the climate of southern Cuba, were obtained in abund- 

 ance both as regards number and variety. A large collection of 

 sugar-canes was secured from a very wide geographical range, 

 and these were placed at once under conditions favorable for 

 attempts at crossing. It is well known that almost all varieties 

 of sugar-cane, now in cultivation, bear only very imperfect flowers 

 which are practically incapable of impregnation without artificial 

 aid. The interesting experiments in Java and elsewhere have 

 shown that by intervention at the right time, it is possible in 

 some cases to secure good seed sparingly, and from these few 

 seeds to obtain varieties which are decidedly promising as regards 

 content of sugar, vigor of growth, and resistance to hurtful influ- 

 ences. The aid of Mr. R. M. Grey, the well known hybridizer, 

 was secured for this work upon cane, and he had access to all the 

 varieties in stock. One very successful result was the production 

 of a strong variety which encourages to further effort. Some 

 doubt was felt at first whether the climatic conditions in Cuba 

 were favorable for the early stages of crossing, but these doubts 

 have been largely dissipated by even the moderate success which 

 Mr. Grey obtained. A good many of his seedlings were not 

 properly cared for by one of the station hands, and were lost 

 shortly after Mr. Grey returned north. 



