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The beak is extremely attenuated and acutely pointed at its termination, the liinge-area 
is comparatively large in the ventral valve, with a longitudinal groove or channel, and the 
surface of areal space is transversely striated, a feature which none of the Scottish 
specimens that fell into my hands for examination presented. In the same locality and 
beds occur, though rarely, Lingula squamiformis and L. mytiloides, Productus Martini, 
and Discina nitida^ so that we have apparently in Northumberland a continuation of 
the same Carboniferous rocks as occur in Lanarkshire and other districts of Scotland. 
In his " Notes on the Genus Lingula " (' The College Miscellany,' No. vii, Glasgow, 
1863) Mr. John Young, of the Hunterian Museum, Glasgow, observes that Lingula 
/Sco/^'crt' is not a common species, and that, in addition to the Lanarkshire localities, already 
named in my Monograph, it occurs on two well-defined horizons, viz. at 239 fathoms and 
300 fathoms below the " Ell coal," and that it has been found at Boghead, near Hamilton, 
and in the Glasgow coal-field at Bobroyston, at 239 fathoms below the "Ell coal." Dr. 
Rankin has also met the shell at Gillfoot, near Carluke, in Lanarkshire. I was likewise 
informed by Mr. Carrington, some short time previous to his death, that he had found a 
good specimen of Lingula Scotica at Gateham, in Staffordshire. 
2. Lingula Thomsoni, Lav. Sup., PI. XXX, fig. 10. 
Lingula Thomsoni, Bav. Trans, of the Geol. Soc. of Glasgow, vol, ii, pi. xi, 
figs. 3, 3 «, b, 1866. 
Shell small, oblong, or slightly longer than wide, broadest anteriorly, sides sub- 
parallel ; beak obtusely angular ; valves slightly convex ; surface longitudinally and 
finely striated. 
Length 4|, width 3 lines. 
Loc. Carboniferous Limestone, Tirfergus Glen, near Campbeltown, Scotland. Of 
this small species I have seen two examples, found by Mr. James Thomson, of Glasgow. 
3. Lingula squamifgrmis, Phillips. Dav., Carb. Mon.,p. 205, PL XLIX, figs. 1 — 10^ 
I have not much to add with respect to this species. In his paper " On the Genus 
Lingula and its occurrence in the Carboniferous Strata around Glasgow " (' The College 
Miscellany/ Glasgow 1863), Mr. John Young observes that L. squamiformis is the most 
abundant species in many localities. " It is found ranging from the horizon of our Lower 
Marine Limestone and shales to the top of our limestones. Lingula mytiloides is not so 
abundant a species in the Glasgow coal-field as the former, but is found in the ironstone 
