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, 

 we have a corresponding diversity of species, and these again are increased 

 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 Range, the basis of which is the Keuper formation rising in a 

 steep incline. The New Red 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, is 

 composed of Palseozoic 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, Knock, 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 Phillips's 1 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, and 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. 



