HARPER: VEGETATION OF THE HEMPSTEAD PLAINS 267 
are generally covered with minute lichens* and an occasional 
patch of moss, which presumably indicates that earthworms are 
rare or absent, for if they were at all common the earth brought 
up by them and deposited on the surface would tend to bury 
these very slow-growing plants. The lack of earthworms is 
probably due to the fact that the loam layer is shallower than the 
depth to which the ground freezes in winter, and the worms if 
present would hardly descend into the gravel to hibernate. There 
are a few ants, but their hills are not numerous enough to interfere 
seriously with the ground lichens. ! 
On account of the porosity of the subsoil every heavy rain 
must carry down into the ground some of the soluble salts, thus 
making the soil progressively poorer. And this tendency cannot 
be counteracted to any considerable extent by capillarity, on 
account of the depth of the water-table, or by the soil fauna 
(as it seems to be in some other ріасев?), for the ants, etc., prob- 
ably do not go down into the gravel much. 
Climate. The climate is cool-temperate, but with a long 
growing season on account of the proximity of Long Island Sound 
and the Atlantic Ocean, neither of which is more than ten miles 
away. There are no weather stations on or very near the Plains, 
but if we take the average of the data for New York City, Setauket, 
and Brookhaven we will probably be not far wrong. The New 
York records were taken from 1826 to 1864 at Jamaica, which is 
within ten miles of the west end of the Plains, and since then on 
Manhattan Island, at a gradually increasing altitude as the build- 
ings became taller. The Brookhaven records cover the period 
from 1864 to 1882, and those for Setauket from 1886 to 1909. 
The data given are the average temperature, in degrees Fahren- 
heit, and precipitation, in inches, for each month and for.the whole 
year. 
Months Temperature Precipitation 
МАО 222222222. 30.4 3.70 
Pop a eaa et е ere 30.0 3.81 
Мами uico Wir ak e Cee es 313 4.31 
АНАР 22222222... 47-9 3-59 
* Mostly Cladonia symphycarpa epiphylla, according to Mr. R. S. Williams, 
who identified a specimen for me recently. The moss is mostly Polytrichum juni- 
perinum. 
f See Ана. Rep. Fla. Geol. Surv. 7: 147. 1915. 
