(he Devonian Rocks of Moravia. 71 



matrix is eliiefly made up of the detritus of the underlying 

 schist, in one of the hai'der fragments of which I observed a 

 portion of a Paradoxides. With some local exceptions and 

 numerous dislocations towards the north-eastern extremity of 

 the tract, there is a more perfect symmetry in the ascending 

 series, on whatever side the section be made, than any other, 

 of the same dimensions and age, with which I am acquainted. 

 I will not here speak at length of the porphyry, kiesil-schifer, 

 hornstone {dc), ttc, which occur on the north-western side of 

 the basin, which with certain bands of heavy, dark, quartzose 

 grauwacke, give a peculiar aspect to the lower portion of this 

 division, as seen between Nyschburg and Skrey ; but I must 

 observe that the iron ores in it are scarcely to be distin- 

 guished in mineral aspect from those of Dillenburg and 

 other places in Nassau. There Bohemian pisolites are, how- 

 ever, quite distinct from those of the Lahn and Rhine, both 

 in geological position and zoological contents ; for they occur 

 in the very heart of the lower Silurian Rocks, and instead of 

 Devonian fossils they contain Echinosphientes, belonging to 

 Cystideas, those earliest cinnoids which have alone been detect- 

 ed in the lower Silurian strata, and which have been so ad- 

 mirably described by Leopold von Bueh. Although this is 

 not the occasion to treat of the influence produced on the 

 marine deposits by the eruption of porphyiy, greenstone, &c., 

 with which this tract abounds, nor of the varied structure 

 and contents of the mineralized distinct near Przibram, I 

 shall, however, presently allude to some igneous evolutions 

 intimately connected with the sedimentary succession. The 

 superior masses of the quartzose series are chiefly character- 

 ised by a pi'ofusion of trilobites, the type of which is the 

 Trinucleus — one species being, in my opinion the T. carac- 

 taci (mihi), and another the T. ornatus (Sternberg). These, 

 with various forms of Phacops, Calymene, Asaphus, and 

 Odentopleura,&c. are associated with the Or this reditx (Barr.), 

 a form similar to one of my Caradoc fossils. It is specially 

 where these quartzose rocks begin to pass upwards into al- 

 ternation with soft black schists, that a new source of interest 

 awaits the geologist. He is here on the upper limit of all 

 those rocks to which tlie term " Lower Silurian" has been 



