abstracts: phytopathology 227 



and later intrusives constitute the rock formations of the basin. The 

 Carboniferous contains red beds and thick ledges of gypsum. Alluvial, 

 lake, and wind deposits and precipitates from solution cover the rock 

 floor of the valley. The lake beds are finely laminated; the wind depos- 

 its include dunes of gypseous dust or clay 100 feet high; the precipitates 

 include one bed of common salt that is commercially valuable. In 

 Pleistocene time a lake 450 miles in area occupied the basin, the strand 

 of which is marked by ancient cliffs, terraces, beach ridges, spits, and 

 bars. Post-lacustrine wind erosion has formed numerous basins with 

 steep walls and flat bottoms that coincide with the ground-water level. 



Encino and Pinos Wells valleys are small undrained depressions east 

 of Estancia Valley. The former held a Pleistocene lake about 18 square 

 miles in area, as is shown by an ancient strand and stratified beds, and 

 has both pre-lacustrine and post-lacustrine wind deposits. Flat-bot- 

 tomed, wind-scooped basins, characteristic of Estancia Valley, are found 

 also in both of these valleys. The susceptibility of the clay to wind 

 erosion is probably due to its gypsiferous character. Typical gypsum 

 sand occurs in the Pinos Wells depression. O. E. M. 



PHYTOPATHOLOGY. — A plant disease survey in the vicinity of San 

 Antonio, Texas. Frederick D. Heald and Frederick A. Wolf. 

 Bulletin Bureau of Plant Industry No. 226, pp. 129, text figs. 2, 

 plates 19. 1912. 

 The authors report a plant disease survey made during the summer and 

 fall of 1909 and the winter and spring of 1910, in the area comprised 

 within a circle having a radius of 100 miles from San Antonio, Texas. 

 This region occupies the coastal plain of Texas in the south and east 

 and extends into the Edwards Plateau and Llano country in the north- 

 west. Maps show the places visited and the rainfall for 1909. Tables 

 give the elevation of the principal stations, the annual precipitation for 

 1909 at 24 points, the maximum, minimum, and mean temperatures, 

 and the average daily evaporation at the San Antonio Experiment 

 Farm. The rainfall of the area studied is limited, ranging for the most 

 part from 20 to 30 inches, while one-half of the area had a total annual 

 precipitation of only 10 to 20 inches. The temperatures in summer 

 are high and the evaporation large. The authors describe the crops 

 and native vegetation of the area, and discuss the relation of the environ- 

 mental factors to the plant diseases found. Chlorosis, probably due to 

 excess of lime and to drought, is one of the most noticeable and charac- 

 teristic pathological features noted. 



