THE CAEBONIFEEOUS FORMATIONS OF THE BRITISH ISLES. 505 



Somerset are found Leperditia OJceni^ L. parallela, L. acuta, Bey- 

 richia arcuata (?), B. sp., Kirhhya plicata, K. costata, Moorea tenuis, 

 M, obesa, Bythocypris bilobata, Aryilloecia cequalis, Cythere ? Imiata, 

 C. ? pyrula, C. ? Moorei, C. ? coniigera, C. ? tJiraso, Bairdia curta, 



B. plebeia, B. brevis, and B. Hisingeri. 



We have nothing in the south representing the large groups of 

 species found in the Yoredale Rocks of the north of England, or of 

 the Carboniferous Limestone series of Scotland. 



.From the Coal-measures of South Wales we have Carbonia Agnes, 



C. Evelince, and C. sp. ; and from the ' Spirorbis Limestone " of the 

 Midland counties Leperditia inflata. 



lY. Irelaxd. 



The distribution of the Carboniferous Ostracoda in Ireland (see 

 Table II.) requires further work. The Mountain-limestone near 

 €ork and elsewhere is known to be very rich in these fossils, as are 

 also some parts of that formation in the Isle of Man. The Lower 

 Carboniferous Shales are rich at places in Ireland (see M'Coy's 

 Synops. Charact. Carbonif. Eossils, Ireland, and Ann. & Mag. jSTat. 

 Hist. ser. 3, vol. xviii. pp. 40-51). 



V. Distribution of Ostracoda in Permian Strata of England. 



To render this sketch of the vertical distribution of Ostracoda in 

 the Upper Palaeozoic rocks more complete, we continue it up to the 

 Permian series, into which eleven of the Carboniferous species are 

 known to range. 



In the Lower Magnesian Limestone of Durham and Yorkshire we 

 find the following species : — KWTcbya permiana, Bairdia plebeia, 



B. Hisingeri, B. ampla, Macrocypris Jonesiana, Cythere intermedia, 



C. ? inornata (?), and Cytherella miciformis ? 



In the Middle Magnesian Limestone of Durham occur: — Cypridina 

 primceva, Kirhbya permiana, Bairdia plebeia, B. Hisingeri, B. acuta, 

 B. Kingii, B. bernicensis, B. rhornboidea, B. amputata, Macrocypris 

 Jonesiana, Cythere? intermedia, C.2 Morrisiana, and (7.? Geinitziana. 



And in the Upper Magnesian Limestone of Durham we have as 

 the last Palaeozoic representatives of the order : — Kirkbya permiana, 



B. plebeia, B. grandis, B. ampla, B. acuta, Cythere ? Morrisiana, 



C. ? Kutorgiana, G. ? Geinitziana, C. ? biplicata, C. ? inornata, and 

 Cytherella nuciformis: 



These occurrences in the Permian series represent a range of 

 about 400 feet. The Ostracods are always found along with the 

 marine Mollusca and other fossils of the Magnesian Limestone ; but 

 where the last representatives of the Mollusca are seen in the highest 

 beds of the series, no Ostracoda are found with them. 



The Carboniferous species recurrent in Permian strata are: — 

 Cypridina primo'va, KirTcbya permiana, Bairdia j)lebeia, B. ampla, 

 B. Hisingeri, B. amputata, B. grandis, Macrocypris Jonesiana, 

 Cythere ? intermedia, and (in the Zechstein of Europe) Bairdia 

 mucronata and B. subgradlis. 



