.,^. LIFE-ZONES IN LOWER PALEOZOIC ROCKS. 131 



Lapworth in i88g. It now remains to apply that method to the 

 more accurate correlation of the strata of the earth's surface, for 

 hitherto the work has been only commenced. The geologist of the 

 future will gather a valuable harvest from the material that his pre- 

 decessors have collected. We must be, in the main, content patiently 

 to collect that material, comforting ourselves with the knowledge that 

 brilliant speculations, founded on insufficient data, have usually but a 

 brief existence, while a collection of accurate facts is of service for 

 all time. We need not fear that our energies will be altogether 

 exerted in cataloguing facts ; every careful piece of work assists in 

 the establishment of some new truth, or the acquisition of fresh ideas. 

 The Stratigraphical Geology of the future will not consist almost 

 exclusively of the enumeration of the order of succession of deposits, 

 their thicknesses, their lateral variations, and their fossil contents. 

 The earth-movements, the vulcanicity, the metamorphic changes, the 

 climatic variations, and the life-history of each period will be more 

 fully elucidated, and the elaboration of a true Earth History will be 

 possible. In the meantime, we rejoice to see Stratigraphy once more 

 placed upon a firm basis, and, while still indebted to her early hand- 

 maid. Palaeontology, having fresh life infused into her by contact with 

 the young and vigorous Petrology. 



REFERENCES. 



1. Barrande, J. — Systeme Silurienne du Centre de la Boheme, vol. i., 1852. 



2. LapiHforth, C. — The Moffat Series. Quart. Joiirn. Geol. Soc, vol. xxxiv., 



pp. 240-343, 1878. 



3. Barrande, J. — Trilobites: Extrait du Suppl. Syst. Sil. Boheme, vol. i., 1871. 



4. Liapivorth, C. — Discussion, loc. cit., vol. xliv., p. 730, 1888. 



5. Marr, J. E. — On Homotaxis. Proc. Caiiib. Phil. Soc, vol. vi., pp. 74-82, 1887 



6. Geikie, A. — Text Book of Geology, 1890. 



7. Suess, El. — Das Antlitz der Erde, vol. ii., 1888. 



J. E. Marr. 



K 2 



