Jackson.] 262 



purpose. Thus the nortliern limit of the grape, both in Europe 

 and America, is nearly coincident with the line of 65°, during 

 those four months, which is the period of flowering and ripening of the 

 fruit. Some varieties of grape require a much higher temperature 

 during the same time. Many other plants are controlled by the same 

 law, but this law in the case of plants is modified by other causes, as 

 moisture, nature of the soil, early or late frosts, etc.* In the eastern 

 United States the lines of average temperature during these four 

 months, coincide nearly with those of the three months which influ- 

 ence birds. Thus the northern limit of grapes (G5°) mentioned above 

 is nearly coincident with that of 50° for birds ; and that of 80° for 

 plants agrees approximately with that of 65° for birds. For this reason 

 we find that the limits of the FlorEe and Faunte are nearly the same 

 in many cases. Thus the limit of the Alleghanian Fauna is also the 

 limit, or nearly so, of the grape, chestnut, hickory, white oak, and other 

 species of oak, and many other species of plants, while the region of 

 the Canadian Fauna is characterized by coniferous forests, and espe- 

 cially by the mixed forests of spruce, fir, larch, and white birch. As 

 many insects and other animals are directly dependent upon particu- 

 lar kinds of vegetation, their distribution must be influenced by the 

 same causes, even if the temperature of their breeding seasons does 

 not affect them directly. 



Dr. Jackson presented specimens of cretaceous fossils 

 Cardium Cooperi Gabb, and Amauro2osis alveolatus Conr, 

 collected by himself at Santa Barbara, and labelled by Mr. 

 Gabb. The chalk formation is overlaid by the miocene 

 strata, where are also deposits of asphaltum and bituminous 

 oil in the cretaceous rocks, the oil rising up through the ter- 

 tiary strata. He also described the Quicksilver deposits of 

 Santa Barbara. He then remarked upon the Borax found in 

 a small lake in Lake County, Cal., which was examined by 

 Dr. Torrey. • This was a shallow lake, with hot mineral 

 springs rising in it, in a region where the soil is charged with 

 carbonate of soda, which unites with the boracic acid thrown 

 up in these springs, thus forming the biborate of soda ; and as 

 the lake dries up, crystals of borax are left in the mud at 

 the bottom. The borax is now obtained by sinking iron 

 coffer dams to the bottom, and then pumping out the water, 

 when the clay is dug out, containing crystals, sometimes as 



*For an exposition of these laws see Articles in the Reports of the Agricultural 

 Bureau of the U. S. 1862, 1863. 



