Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne (1867).djvu/67

Rh 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 is the most noteworthy. The Midagrarian zone includes the low country 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-country 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 propose, 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 boundary 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, furnish 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, Bywell, 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