122 The Principles of Fruit-growing. 
dates. By ‘earliest’ is not meant the first frost in 
the spring, but the earliest date at which the season 
has opened, while when applied to the fall it is the 
first actual occurrence of a frost. By ‘latest’ is 
meant the last occurrence of a killing frost in the 
spring, and in the fall the latest date at which the 
season has closed. The average date is in most 
cases the mean of average dates given by the Weather 
Bureau. 
“The states have been grouped into three regions, 
the states of the coast plain, the states of the Ohio 
River basin and its adjuncts, and the states of the 
Missouri River and its adjuncts. The first thought 
in separating the states into these regions was that 
they represented distinct faunal regions, and that 
they probably represented distinct climatal regions. 
This has been sustained in most part. The most 
marked cases are eastern New York, or the Hud- 
son Valley, and western New York, the former be- 
longing to the coast states and the latter to the 
Ohio valley states. There is a difference of eleven 
days in the spring on earliest dates, twelve days 
on latest, and two days on average; Pennsylvania, 
which falls in the same category, in the spring, 
fifty-four days on earliest, eleven days on latest, and 
twenty days on average dates. In the other regions 
the difference is not so marked, and yet there is 
some difference in all cases. 
“This tabulation is of interest in showing the 
earliest and latest dates at which the seasons have 
opened, for some of the data is based on records 
