240 
THE GEOLOGIST. 
classes of plants growing over the surface do not necessarily, and very 
commonly do not, represent the varieties of the rocks constituting the main 
geological structure of the county. Wherever a diversity of rock occurs, 
vre have a corresponding diversity of species, and these again areiucreased 
or diminished in numbers in accordance with the amount of disintegration 
suffered, the capacity to imbibe water, and other conditions of the rocks. 
The district under consideration is divided by the Belfast Lough and the 
river Lagan into two well-marked sections, both as to the geological strata 
and as to geographical relations. The northern section is occupied by the 
Belfast Hill Eange, the basis of which is the Keuper formation rising in a 
steep incline. The JN^ew Hed is surmounted by the Lias, the Upper Cre- 
taceous rocks and Basalt forming a bold escarpment extending from White- 
head to Lisburn, with an average elevation of a thousand feet, from the 
heights of which the land slopes gently inland, forming plateaus of great 
extent. The southern section, excepting some patches of the newest 
Tertiaries in the neighbourhood of Bangor and in the Knock Valley, ia 
composed of Palaeozoic rocks. Surmounting the Silurians are the free- 
stones of the Old Red Sandstone, in some places capped by Greenstone 
Porphyry, a mere strip of Carboniferous Limestone occurring at Castle- 
Espie. Beds of the Permian age occupy the coast-line at Caltra. The 
districts of Lagan, Xnock, Ballyaholly present extensive marshes, and 
peat-bogs are encountered at high elevations in the northern section, as on 
the Black Mountains. With a region so varied in its geological surface, 
and so diversified in its physical aspects, we might expect to find a great 
variety and diversity of plants ; and so it is : Mr. Tate records 602 species. 
Professor Phillijjs's ' Guide to Geology.'' 
There is no book we know of more worthy to be put in the hands 
of beginners in geology than the pretty work of Professor Phillips, the 
fifth edition of which is now before us, nor is there any more fitted for 
giving a rudimentary knowledge to the general public, especially such as 
wish to get sufficient knowledge to understand the main discussions of 
such importance as are now being carried on. Professor Phillips's long 
experience as a teacher has well fitted him for giving such instruction. 
He is an acute thinker, a voluble speaker, and possesses a love of his 
science and great earnestness. There is a tendency in his thinking 
towards speculativeness which makes his writings more suitable to the 
understanding of ordinarily educated persons, an& peculiarly pleasant to 
those who wish to understand the controversies of the day. At the same 
time the main philosophical principles of geology are not neglected, and 
the object of the science, the earth's condition as a planet considered, and 
the nature and character of the primitive land discussed ; the elementary 
substances which enter into the composition of rocks, their stratigraphical 
arrangement given, the origin of rocks stratified and unstratified, the phy- 
sical geography and general structure of the earth pointed out. The sub- 
aqueous production of land, its elevation, the relative antiquity of its 
various portions, the changes of climate, the series of life and vegetation 
which have existed in past time, the various proposed methods of estimat- 
ing the lapses of geological time, are other subjects equally well and clearly 
treated, the last two chapters being devoted to lithology, and to tables 
and calculations. 
