500 PEOF. T. R. JONES AND MR. J. W. KIEKBT ON OSTRACODA OF 



nearly 4000 feet of strata exposed below the Carboniferous Lime- 

 stone series. In the lowest of these strata, the first Ostracod to 

 appear is a very simple Beyrichia, identified with B. suharcuata. 

 Pifty feet or so higher up is a shale containing Carhonia fahulina 

 and C. RanJciniana. A few feet further up still, in a " cement- 

 stone," B. suharcuata again appears along with Leperditia OTceni 

 and Bairdia nitida. These are the earliest traces of Ostracoda in 

 the Carboniferous Series of the east of Scotland that have come 

 under our observation. 



A few hundred feet higher up — though still from 3200 to 3500 

 feet below the Carboniferous Limestone series, and in a section 

 where several thin limestones with marine fossils come in, the fol- 

 lowing species are found, and they may probably be taken as repre- 

 sentative of the earliest important group of Carboniferous Ostracoda 

 in Scotland : — 



Leperditia Okeni *. 



scotoburdigalensis. 



Beyrichia subarcuata ? 



, sp. 



Kirkbya spiralis. 

 ■ plicata. 



Cytherella extuberata. 



attenuata. 



Carbonia subula. 



Bairdia plebeia. 



Hisingeri. 



siliquoides. 



prsecisa. 



subcylindrica ? 



Macrocypris Jonesiana. 

 Argilloecia sequalis. 

 Aglaia cypridiformis. 

 Cythere ? intermedia. 



Carhonia suhula occurs in this series of strata, but not associated 

 with the other species of the list.- 



For the next 1000 feet or more upward, Ostracoda appear and re- 

 appear time after time, and in great individual abundance. Species, 

 however, are not numerous. Among the commonest forms are 

 Leperditia scotohurdigalensis^ Beyrichia suharcuata, Cytherella ex- 

 tuherata, and C. attenuata. On some horizons they are joined by 

 Kirhhya spiralis and CytJiere? superha, and perhaps one or two others. 

 At one spot, in a " cement-stone," these species give place to Leper- 

 ditia OTceni, BeyricJiiopsis Jimhriata, a Cytherella, and one or two 

 BairdicB. Besides, at intervals, those Coal-measure Cytherids (?), 

 Carhonia fahulina and C. RanJciniana, keep coming in along with 

 C. suhula. The Leperditia^ and other species generally go out as 

 these appear, though not in all cases. 



Above all this, near the middle of the Calciferous Sandstones 

 (speaking of Mfe), in a thick marine shale with Crinoids and 

 numerous other fossils are these species : — 



Leperditia Okeni. I Bairdia plebeia. 



Beyrichia radiata. i Hisingeri. 



subarcuata ? | brevis. 



Cytherella, 2 spp. | subelongata. 



Then followmore appearances of Lep. scotoburdigalensis and its asso- 

 ciates before mentioned, — though not all of them, for KirJchya spiralis, 



* For the authorities of species, see Table II. at the end. 



