THE CAKBOiarEROUS rOKMATIOSTS OF THE BKITISH ISLES. 499 



stratigraphical succession of their different groups of species or 

 faunas is a subject well worth working out in detail ; and this we 

 hope some time to do with the help of our Geological-Survey friends. 

 In the centre and south of England, — that is, south of Derby- 

 shire, — the Yoredales are absent, or cease to be of divisional im- 

 portance in the Carboniferous series, so that the arrangement of 

 formations there generally followed is this : — 



Coal-measures. 

 Millstone Grit. 

 Upper Limestone-shale. 

 Carboniferous Limestone. 

 Lower Limestone- shale. 



Unfortunately we have much less material of the Ostracodous kind 

 from the south of England than we have from the north, and from 

 Scotland, and most of what we have is from the Carboniferous Lime- 

 stone, there being little from the Coal-measures, and nothing from 

 the Millstone Grit or the Lower Limestone-shale. Eor this reason, 

 the distribution of species in the appended Table I. (facing p. 506), 

 is shown in two columns only — Carboniferous Limestone and Coal- 

 measures. 



For the same reason the Lower Limestone-shale is left out of the 

 Table in "England North," as we have nothing from localities 

 therein. And, as we have not been able to determine any species 

 from the Millstone Grit either in England or Scotland, that for- 

 mation is not represented. See p. 514. 



All our Irish specimens are from the lower portion of the series, 

 hence the distribution in that country is given in a single column. * 



In regard to the geographical divisions used in the Table, " Scot- 

 land East " includes Fife, Kinross, Linlithgow, Mid and East Lothian, 

 Berwickshire, and Eoxburghshire. " Scotland West " includes the 

 country to the west of that area : namely, Lanarkshire, Stirling- 

 shire, Renfrewshire, Ayrshire, &c. 



" England North " takes in Lincolnshire, Notts, Derbyshire, North 

 Staffordshire, and the counties to the north ; also the Isle of Man. 

 " England South " embraces the rest of the country southward, in- 

 cluding South Wales. 



III. StKATIGEAPHICAL DiSTEIBUTIOIf OP THE OsTKACODA. 



I. Scotland. 



§ 1. South of the Firth of Forth, the Upper Old Red is described 

 by Dr. A. Geikie * as passing upwards into the lowest beds of the 

 Carboniferous Series without any signs of break or unconformity. 

 Probably these are the lowest and oldest Carboniferous strata in 

 Scotland ; but there are no Entomostraca recorded from them. 



In Fife, where the Lower Carboniferous or Calciferous Sandstone 

 series is very thick, the basal beds are never seen, though there are 



* Geol. Survey Mem. on East Lothian, p. 27 (1866). 



