NOETHUMBERLAND AND DURHAM. 49 



The Inferagrarian zone embraces all the wide area south of the 

 estuaries of the Dee and Humber, with the exception of some of 

 the "Welsh, Cornish, and Devonshire hills. There are a large 

 number of species peculiar to it, of which Clematis vitalha is the 

 most noteworthy. The Midagrarian zone includes the low coun- 

 try in the North of England and southern half of Scotland, and the 

 Superagrarian zone the low ground of the North of Scotland ; and 

 both of them belts of corresponding temperature in the hill-coun- 

 try of the more southern latitudes. In some counties, in at least 

 half of the English ones, for instance, we get only one out of 

 these six zones ; but there are at least two of them in any county 

 where the hills reach a height of 1000 feet. In our own two 

 counties, beginning to count from below, we get the second, 

 third, and fourth, but not the first, fifth, and sixth. We pro- 

 pose, in the present work, to call these zones which we have 

 simply Lower, Middle, and Upper, and to regard the contour- 

 lines of 300 and 600 yards above sea-level as forming the boun- 

 dary between them ; and these will be the same as "Watson's 

 Midagrarian, Superagrarian, and Inferarctic zones. 



Mean Temperatures in the Shade. — The following table of mean 

 temperatures is taken from the Reports of the Registrar General, 

 from 1860 to 1864 inclusive. These tables, which are published 

 quarterly by Government, under the editorship of Mr. Glaisher, 

 contain regular observations from a large number of stations 

 scattered up and down the island, and, gathered together, fur- 

 nish the most complete and reliable data upon its climate which 

 are in existence. Although only four of the stations come within 

 the limits of our field of study, it fortunately chances that these 

 are excellently adapted for showing what we want to know, one 

 of them, North Shields, being on the sea coast; a second. By well, 

 inland, in a sheltered position, at a very trifling elevation; a 

 third, Alnwick (the observations are made at High House, 350 

 feet above sea-level), more northern and exposed; and the. fourth, 

 Allenheads (1350 feet above sea-level), being the most elevated 

 locality in Britain where careful thermometric registration has 

 been carried on for any considerable length of time. To these 



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