XXX PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



scarcely judge of their minuteness and importance until he com- 

 menced to send them forth in full. He now takes his place definitely 

 in the foremost rank of geologists and palaeontologists. He combines 

 in a remarkable degree both qualifications, — no small advantage when 

 the wide general views and the classification of great formations, such 

 as are dealt with by this eminent man, have to be fully considered 

 and put forth with ample arguments. Division of labour is good for 

 the accumulation of sound and abundant materials, but experience 

 has shown in both geology and the other sciences, that the greatest 

 advances are to be made by combinations of kinds of knowledge 

 in those who deal with the greater problems. M. Barrande has 

 done well, it seems to me, by pursuing assiduously the double course 

 he has chosen. The main body of the purely geological portion of 

 his work he proposes to publish when the palseontological details, 

 which constitute most of the evidence upon which his views are 

 founded, have been laid before the geological world in all their com- 

 pleteness. The task he has before him in this respect is a laborious 

 one ; no less than the detailed description and critical investigation 

 of some 1200 species of fossils, — for such is the number that has 

 rewarded his search in Bohemia. The natural history and principal 

 part of his first volume, a bulky work in itself, is devoted to the order 

 of Trilobites. It is prefaced, however, by a general outline of the 

 geology of Bohemia, which first deserves our notice, both on account 

 of the interest it must present to British geologists dealing with 

 palaeozoic strata, and also because of certain original and peculiar 

 views put forth in it. 



The Silurian formation of the centre of Bohemia constitutes a well 

 defined basin of an elongated oval shape, the great axis of which is 

 directed nearly N.E. and S.W., and has a length of about 20 German 

 geographical miles with a maximum breadth of 10. It is from 55 

 to 60 miles in circumference. Towards the N.E. and N. a small por- 

 tion is bounded by the Trias, the Quader-sandstone, the Planer-kalk, 

 or by the Carboniferous formation. Elsewhere, for two-thirds of its 

 margin, granite or primordial crystalline rocks, such as gneiss and 

 mica-slate, constitute its base and its boundary. A few small carbo- 

 niferous basins are sprinkled over the SUurian surface, as well as a 

 few isolated outliers of cretaceous beds. The dip in the two halves 

 of the basin, the one to the N.E. and the other to the S.E. of the 

 chief diameter, is towards the principal axis. The beds ordinarily lie 

 at an angle of from 30° to 45°, often 70°, and are not unfrequently 

 vertical. 



M. Barrande distinguishes eight stages of strata to which he assigns 

 a Silurian age ; four of them he regards as Lower Silurian, and four 

 as Upper Silurian. Of his Lower Silurian stages the two lowermost 

 are azoic, the distinctions between them being fomided on mineral 

 characters, the first being composed of crystalhue rocks, and the 

 second of clay-slates and conglomerates, similar to the fossiliferous 

 Silurian above them, but wholly void of organic remains. They are 

 rich in lead mines. These azoic stages pass into each other, and the 

 upper section passes gradually into the fossiliferous beds above. 



