616 J. E. MAEE ON THE PKEDEVONIATT 



is only seen at the summit of the cliff, and does not occur at the 

 bottom. The junction between this part of the colony and the 

 beds of cZ 5 is distinctly shown. The beds of the colony are here 

 nearly vertical ; those composing the main mass are blackish sandy 

 shales, weathering yellowish brown. At what M. Barrande con- 

 siders the top of the colony, there are nodules of limestone and 

 some bands of calcareous grit very much disturbed, and these are 

 not continuous, but abut in places against the beds of d 5. This 

 might be due to an unconformity ; but I considered it to be due 

 to a fault, which must have a very clear fracture. A fault, more- 

 over, would account for the disturbance of the beds, which an 

 unconformity does not. This fault would be continuous with that 

 supposed to let down the beds forming the colony at Hodkovicek ; it 

 is, however, here slightly reversed. The limestone nodules yielded 

 the following Graptolites : — 



Monograptus colonus, Barr. I Monograptus Roemeri, Barr. 

 boLemicus, Barr. \ Flemingii ? 



These, along with Cardiola interrupta, Naticella tuhicina, &c., indi- 

 cate distinctly the Colonus-v.oTve. At the other end of the colony 

 is a fracture indicated by a small spring which trickles down a 

 mossy hollow in the side of the cliif and contains pieces of a fault 

 breccia. On the other side of this again are grits of d 5 and also 

 some black shales, not very well exposed, and in which I found 

 no fossils, but which I believe belong to the Diplogi-ai^tus-zone, 

 for M. Barrande records Diplocjraptus palmeus, Barr. {= folium, 

 His.), from this colony. It seems to me, then, that the colony was 

 produced in the same manner as that at Hodkovicek, of which it 

 is probably the continuation, but that after its formation the second 

 fracture occurred, cutting off some of the Colonus-zo-ne, all of the 

 Priodon-zone, and most of the Di^lograjptus-zone, and giving the 

 first fault its slight reversal. 



At the summit of the cliff-section exhibiting this and the next 

 colony is a tableland covered with corn-fields, so that the colonies 

 here cannot be traced along their strike to the S.W. 



9. Colonie Haidinger. — A mass occurring in the same river-cliff 

 with Colonie Krejci, and a few hundred yards t6 the S.S.W. of the 

 latter. Its section is described by M. Barrande (Def. des Col. iv. 

 p. 59). It consists entirely of the black "wafer" shales charac- 

 teristic of the base of the I)iplograptus-zor\e. I saw the outcrop of 

 a clean-cut fault between it and the beds of d 5, which are supposed 

 to surmount it. I consider this colony, then, to be the lowest 

 subzone of the Biplograjotus-zone at the base of e 1 faulted down 

 against the beds of d 5. I give a section from the Silurian base of 

 the Slivenec valley, across colonies Krejci and Haidinger, showing 

 the view entertained as to the explanation of these colonies (fig. 10, 

 p. 615). 



M. Barrande records only Graptolites from Colonie Haidinger (Def. 

 des Col. iv. p. 60). By the kinduess of Herr Husl of Beroun, I have 

 been enabled to make a larger list of fossils, all of which, save one, 

 are in the magnificent collection of that geologist. Many of the 



