Messrs. Jones and Kirkby on Carboniferous Entomostraca. 47 
_ 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 Scotoburdi- 
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, 17, & 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 R. 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. 
ee 22, Sir R. Griffith states that ntomoconchus 
Scouleri occurs in the Lower Limestone of the southern and 
middle districts of Ireland. 
Bairdia curta occurs in the middle and northern. 
gracilis of northern. 
Cythere cornuta _,, northern. 
inflata Fe southern and middle. 
imornata a northern. 
spinigera Pe 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 
