SOME PECULIARITIES IN THE RAINFALL OF TEXAS. 61 
than .006 inch, practically nil. Your attention is invited to 
the abrupt increase of August, due to the intrusion of the 
Trans-Pecos type, and a less decided increase during Octo¬ 
ber, probably resulting from the interference of the Gulf type. 
In lower New Mexico and the Trans-Pecos region of Texas 
another type of rainfall obtains, which at first glance would 
appear to be the Gulf type slightly modified by the increased 
distance inland. The month of maximum precipitation is in 
late summer, August or September, and the rainfall is pro¬ 
portionally even greater than that of the coast of the Gulf of 
Mexico. The minima occur somewhat irregularly, according 
to locality, from December to May. It is, however, a different 
type that will be referred to as the Trans-Pecos. While it 
obtains from Fort Stockton, near the Pecos, westward to El 
Paso, its best example is the Fort Davis curve, herewith pre¬ 
sented. The most marked characteristic is the extremely 
disproportionate excess during August (.087 inch), which ex¬ 
ceeds by more than 75 per cent, the next greater excess 
(.049 inch) in September. The winter deficiencies are more 
persistent than those of the Panhandle, as represented by 
Fort Elliott, extending from November to April, inclusive, 
with an extreme difference in the values of these months of 
only .008, an inappreciable amount. 
It appeared remarkable on first consideration of the sub¬ 
ject that extreme western Texas should be favored with a 
far greater part of its rain in summer, and in connection 
therewith should have during July and August a larger 
number of rainy days than is experienced in the eastern 
part of the State. A thorough investigation proves quite 
conclusively that this western region shares the rainfall 
regime of New Mexico and western Arizona, and a further 
examination makes it evident that the ultimate source of 
precipitation in the Trans-Pecos type of rainfall is not the 
same as that for eastern Texas—the Gulf of Mexico. 
No doubt exists in the mind of the writer that the summer 
rains of Arizona and southern New Mexico depend on ab¬ 
normal barometric conditions, central during that season in 
10—Bull. Phil. Soc., Wash., Vol. 12. 
