SUESS — DISTEIBUTION OF THE BEACHIOPODA. 



291 



three BiscincB, one LinguJa, five OrtJiides, two Leptcenw, and two 

 donbtful species. You remark exactly the same association of the 

 shallow- water group A with the intermediate forms, which I have 

 abeady pointed out several times. 



M. Barrande knows thirteen or fonrteen species of Brachiopoda 

 fi'om d 5, one of which is Discina scrohicidosa from d 4i, one or two are 

 IdiigidcB, fom* Orthides, and four other Stropliomenidce, among which is 

 the recurrent Lept. aquila, and two doubtful species. I need not say 

 that it is again a quite similar association, excluding the formation 

 from deep sea condition. Finally, M. Barrande has a short time ago 

 mentioned a new Lingaila in chloritic quartzite belonging to etage D. 



ISTow it is the bed d 4 which, as M. Barrande has taught us, con- 

 tains intercalations of slates with calcareous nodules, which have 

 yielded four new species of fossils, four species identical with those of 

 etage D, and not less than sixty species which have never been found in 

 d 4, nor even in 5, but only in the overlying Upper Silurian etage 

 E. Among these sixty species are eleven Brachiopoda : Terebrat. 

 Daphne, T. linguata, T. monaca, T. ohoUna, T. ohovata, T. reticularis, 

 Siyirlfer togatus, Orthis mtdus, Lept. euglyplia, patricia, and L. 

 Haueri. Not one member of the shallow- water group A, and only 

 one single Orthis are among these eleven species, several of which are 

 8piriferidcE ; T. Daphne is a Bhynchonella. In this hst the predomi- 

 nance of group B is, indeed, very clear. 



As, I believe, M. Barrande' s suggestion is now generally acknow- 

 ledged, that the fauna d 4i, and at least a part of the Upper Silurian 

 fauna B must have lived at the same time, I presume, farther, that 

 this part of the fauna E must have Hved in a someiohat deeper part 

 of the sea than the contemporaneous littoral or sub-littoral fauna d 4i 

 and d 5, and I regard these "colonies" as the intercalations of the 

 deposits of a somewhat deeper bathymetrical zone between sub- 

 httoral deposits. 



In perusing that highly instructive comparison between the 

 Silurian beds of Bohemia and Scandinavia^ which M. Barrande pub- 

 lished a few years since, it is seen that the primordial faunee of both 

 countries consist of very closely representative, but not identical, 

 species.* The same is the case with the second or lower Silurian 

 faunae, although here, perhaps, a small number of identical species 

 may be found. The comparison of the third or Upper Silurian faunaa 

 yields quite another result, as the number of identical species in both 

 countries is by far greater, although small in comparison to the 

 locahty of these faunaa. M. Barrande teaches that with few excep- 

 tions (one Trilohite, two Orthocerata, and a somewhat greater number 

 of Corals), these identical species belong to the class of Brachiopoda, 

 not less than eighteen of which are enumerated as occurring simul- 

 taneously in the Upper Silurian beds of Scandinavia and Bohemia. 

 I suppose eight of them to be Spiriferidce, three BhynchoneUidce, and 

 seven Strophomenidw, among which are two OrtJiides. The group A is 



Perhaps with one single exception. 



