Messrs. Jones and Kirkby on Carboniferous Entomostraca. 4:7 



Thus it will be seen that we refer figs. 12, 13, 14, 15, 18, 21, 

 22, 23, 24, and 25 to Leperditia Okeni without any doubt. 

 They comprise the varieties subrecta (Portlock) and Scoioburdi- 

 galensis (Hibbert). The locality of fig. 23 is not mentioned; 

 but all the others are from shales either of the "Yellow Sand- 

 stone,'' of the " Carboniferous Slate " (fig. 14), or of the " Middle 

 Carboniferous Limestone'' (figs. 21 & 25). Figs. 10, 11, & 16 

 are also in shales belonging to the " Yellow Sandstone." 



Figs. 4, 6, 1 7, & 20 refer to specimens in limestone — from the 

 "Lower Carboniferous Limestone" ^figs. 4 & 17), the " Carbo- 

 niferous Slate " (fig. 6), or the " Middle Carboniferous Lime- 

 stone" (fig. 20). Of the locality and matrix of figs. 5, 7, 8, & 

 23 we have no indications. 



In his ' Notice respecting the Fossils of the Mountain-Lime- 

 stone of Ireland,' &c. (4to, Dublin, 1842), Sir K. Griffith thus 

 divided the Lower Carboniferous formation of Ireland (p. 4). 



1. Upper Limestone. 2. Calp or Calp-slate, consisting of 

 alternations of shale and argillaceous limestone, with occasional 

 beds of pure limestone and rarely of sandstone — and less per- 

 sistent than the Upper and Lower Limestones. 3. Lower Lime- 

 stone. 4. Carboniferous -Slate, or schistose beds, usually calca- 

 reous and alternating with argillaceous limestones, similar to 

 those of the Calp. 5. Yellow Sandstone, consisting of sand- 

 stones intercalated with slate or shale and occasionally with 

 limestone. Nos. 4 & 5 are wanting in some localities ; and 

 sometimes No. 4 only is wanting. (See also Sir R. Griffith's 

 Geological Map of Ireland, with its marginal explanations, 

 1854.) 



At page 22, Sir R. Griffith states that Entomoconchus 

 Scouleri occurs in the Lower Limestone of the southern and 

 middle districts of Ireland. 



Bairdia carta occurs in the middle and northern. 



gracilis „ northern. 



Cy there cornuta „ northern. 



inflata „ southern and middle. 



inornata „ northern. 



spinigera „ northern. 



These determinations were modified probably, and corrected, 

 in Prof. M'Coy's Memoir (1844), and in Sir R. Griffith's List 

 of Localities ' in 1860. 



The Geological Surveyors of Ireland, however, have found it 

 impracticable to fully adopt Sir R. Griffith's nomenclature of the 

 Lower Carboniferous formation. According to their experience, 

 his " Yellow Sandstone " is not sufficiently definite in its upper 



