liv PROCEEDINGS OE THE GEOLOGICAL SOCIETY. 



presume on this occasion to discuss the general question of M. Bar- 

 rande's Colonial System, but shall endeavour to confine myself to a 

 general sketch of the contents of the work and of the objects which 

 he has in view. The etages G and H, it is well known, represent the 

 upper portions of the Upper Silurian formation, or the " faune troi- 

 sieme " of M. Barrande. The work is divided into two parts ; the 

 first is devoted to the general description of the etages G and H on the 

 surface of the Bohemian basin. The first two chapters give the 

 results of his stratigraphical and palseontological investigations with 

 regard to these two groups and their subdivisions. In the third chap- 

 ter he points out their topographical extent, and shows their horizon- 

 tal and vertical relations by means of two sections across the upper 

 division and the zone of the colonies, the one following the valley 

 from Tachlovitz to Radotin, and the other through the quarries of 

 Dvoretz and Branik, near Prague. In the fourth chapter the author 

 endeavours to ascertain whether the etages G and H are represented 

 in the Silurian basins of other countries ; and in the fifth chapter he 

 discusses the connexions which exist between the fauna of the etages 

 G and H and the Devonian fauna. The second part contains an 

 account of his special observations respecting the phenomena of the 

 etages G and H in the neighbourhood of Hlubogep, with remarks on 

 the adverse criticisms of MM. Lipoid and Krejci respecting the 

 stratigraphical arrangement of the beds in question. 



The colonial system of M. Barrande is too well known to geolo- 

 gists to render it necessary for me to make any further allusion to 

 it than to refer you to the last edition of Sir R. I. Murchison's 

 ' Siluria,' p. 400. The anticolonial argument which MM. Krejci 

 and Lipoid have brought forward, founded on the stratigraphical 

 appearances of the different formations in the neighbourhood of 

 Hlubogep, is thus stated by the author : — 



1. There are evident dislocations at Hlubogep in the etages G 

 and H. 



2. These dislocations have produced a mechanical intercalation of 

 the schistose beds of H amongst the limestones of G, showing 

 appearances perfectly resembling those of the colonies. 



3. The colonies are therefore naturally explained by simple dislo- 

 cations and mechanical intercalations. 



These statements M. Barrande emphatically denies. He shows 

 that the supposed existence of these dislocations is solely founded on 

 a want of careful observation. Independently of the synclinal fold 

 already pointed out, along the axis of the basin, and the anticlinal 

 fold, now described in the heights of Divgi Hrady, these pretended 

 dislocations and their supposed effects are purely imaginary. 



Kor does the locality of Hlubogep offer any intercalation what- 

 ever of the schists of H amongst the limestones of G; on the 

 contrary, this locality shows on each side of the synclinal axis of 

 the valley the regular and symmetrical series of the formations of 

 the etages G and H, without any appearance of mechanical origin 

 which could reproduce the stratigraphical and palseontological alter- 

 nation of the colonies. The series of formations near Hlubogep is of 



