TESTING GRAPE VARIETIES IN" THE VINTFERA REGIONS. 



gravelly clay loam or heavy loam, containing a large quantity of 

 organic matter formed in a swamp or lagoon extending in past geo- 

 logical ages up Napa Valley from San Pablo Bay, typical of the greater 

 part of the soils in the valley floor. On weathering, the shales, sand- 

 stones, limestones, lime conglomerates, and large quantities of usually 

 lenticular or angular gravel with little erosion of edges are washed 

 down from the steep hills or mountains surrounding Napa Valley on 



COUNT/ES IHD/GATED ON MAP 

 BY NUMERALS AS FOLLOWS 



A3 COUtSTV- 

 / 0/MAtG£__ _ 



MECCA 



J** If 



II / ° £LCE*7HO\ 



Fig. 1. — Map of California, showing (by large black dots) the location of the twelve experiment vine- 

 yards of the Bureau of Plant Industry. 



all sides except the south, and tend to form a heavy or clayey soil with 

 only small quantities of sand. No hardpan or alkali appears. The 

 surface is undulating, affording a fairly rapid run-off of surplus rain- 

 water, though in places the subsoil is quite wet during the spring 

 months. No irrigation is necessary. The clay and silt in the sub- 

 soils greatly aid in retaining moisture in spite of the large quantity of 



