614 J. E. MAPvE ON THE PEEDEVONIAN 



rocks and drift. It may possibly be an extension of Colonic D'Ar- 

 cbiac. There is no exposure showing the junction of the beds of the 

 colony with those of d 5 to the S. of it. To the N. green shales are 

 seen in conjunction with black Graptolitic shales, near some houses 

 to the N. of the church. These green shales, however, do not ap- 

 pear to belong to d 5, but to be interstratified with the Graptolitic 

 shales, as at Litohlav. They contain poorl}^ preserved Graptolites. 

 I was unable to procure any specimens from this colony sufficiently 

 perfect for identification. 



To the S. of the Silurian basin, passing from E. to W., the first 

 colony met with is 



6. Colony of BraniTc. — This is not now exposed, although the dia- 

 bases connected with it are well seen in the village of Branik, on 

 the E. side of the Moldau, two or three miles south of Prague. The 

 colony is surrounded by alluvia] deposits. The only Graptolites 

 found by M. Barrande belong to the species Monograptus colonus, 

 Barr. They occur in a sandy and calcareous shale. 



7. Colony at Hodkoviceh. — This occurs to the S.W. of that last 

 described and near the river Moldau. Diabases connecting the two 

 colonies can be traced, by their features, passing through the alluvial 

 deposit. The figure (fig. 9) shows a section across this colony ; the 

 faults to the N.W. are seen in a small quarry. Only the upper 

 part of the lowest {Diplograptus) zone is exposed ; it is in close 

 proximity to the base of the Priodon-zone. It consists of black mud- 

 stones, breaking into prismatic fragments, and containing 



Monograptus spinigerus, Nich. I Monograptus triangulatus, Harhi. 

 Becki, Barr. \ turriculatus, jBarr. 



In the Priodon-zojie are many masses of diabase. A large quarry 

 facing the river shows this zone ; it consists of black flaggy shales, 

 containing 



Monograptus priodon, Bronn. I Eetiolites Geinitzianus, Barr. 



' vomerinus, Nich. \ 



The Colonus-zoTiQ was seen, at the time of my visit, in a small 

 gravel-pit in the alluvial plain ; it consisted as usual of sandy shale, 

 weathering to a yellowish brown, and contained numerous speci- 

 mens of Monograptus colonus, Barr. Wo fault is seen, as the section 

 is covered by the alluvial soil; but the dotted fault, if existing, 

 would give sufficient explanation of the phenomena observed in 

 this locality. Unfortunately we cannot get any direct evidence of 

 its existence, for before the alluvial soil ends to the eastward, a 

 large N. and S. fault (the Branik fault of Barrande) would cut 

 it off. 



8. Colony KrejU. — This colony, which is seen in a cliff-section to 

 the south of the village of Gross Kuchel, is in the line of strike of 

 the colony at Hodkovicek, from which it is distant more than a 

 mile, the Moldau with its alluvial plain intervening. 



I could not, during my short stay in Bohemia, form any certain 

 opinion of the explanation of this colony. The section is described 

 by M. Barrande (Def. des Col. iv. p. 60). His upper band of trap 



