574 T, R. JONES AND J. W. KIRKBY ON 
This description applies most exactly to the more typical ex- 
amples, which are always to be distinguished by their nearly straight 
backs, regularity of height, and well-rounded anterior ends. 
Specimens, however, occur whose backs are decidedly curved, 
whose height is not so equal throughout, and whose anterior ends 
lose the normal broadly rounded form of typical examples. Possibly 
such specimens (figs. 6, 8, 9) may represent a variety; but, as their 
lateral contour shows ‘little or no variation, we look upon them as 
not showing too great a divergence from the type of this species. 
Other specimens, while retaining the almost straight and parallel 
borders of the species, possess more pointed posterior extremities, 
as shown in figs. 7 & 10. 
We were once inclined to look upon the examples having a convex 
dorsal border as probably the same as Miinster’s B. suber ylindrica ; 
but that species has the dorsal border more finely arched, a smaller 
anterior extremity, and a more convex lateral contour than any of 
the elongate forms of Bairdia we are noticing. ‘This will be seen 
on comparing the latter with figures 14 & 15, which are from a 
Bavarian example of Miinster’s species. 
Figs. 12, 13, inserted for comparison, represent what we con- 
sider to be an elongate form of B. Hisingert, from Campsie. 
Localities of B. subelongata. 
Wales. In Carboniferous Limestone, at Great Ormes Head, Caer- 
narvonshire. 
Scotland. Carboniferous Limestone (Upper): Ravenscraig, near 
Kirkcaldy, Fifeshire; Levenseat Limestone-pit, Mid Lothian; River 
Avon, below Kinneil Mill, Linlithgowshire; Garple Burn, near 
Muirkirk, Ayrshire; Orchard, near Pollokshaws, Renfrewshire ; 
Gare (Carluke), Meikle Harnock Burn, Climpy (Wilsontown), Gill- 
pott (Carluke), Auchenbeg (Lesmahagow), in Lanarkshire. 
Carboniferous Limestone (Lower): Seatield Tower and Inverteil 
Quarry near Kirkcaldy, Abden near Kinghorn, Pitlessie Quar- 
ries, Wilkinson Quarry near Cupar, Ladedda Quarry near Cupar, 
Woodtop Quarry (Teasses), St. Monan’s, Woodend Quarry near 
Fordel, Charleston Quarry, in Fifeshire; Brunston Colliery, Blink- 
bonny Quarry, Darcy Quarry (8.W. of Dalkeith), Magazine Lime- 
works, Mount Lothian, Baad’s Mill, Mansfield, Fullarton, Cur- 
rielee, in Mid Lothian; Catcraig Land Quarry, near Dunbar, in 
East Lothian; North Mine Quarry, Galabraes Quarry, in Lin- 
lithgowshire ; Craigenglen (Campsie), Corrieburn, in Stirlingshire ; 
Carlops Quarry, Whitefield Old Quarry, in Peeblesshire; Calder- 
side Quarry, Boghead (Hamleton), Kast Drumock, Hillhead Quarry 
near Wilsontown, Ponfeigh Burn and Craigburn near Douglas, 
Fulwood and Braidwood (Carluke), Mousewater near Lambeatch, 
Sheills, Brankumhall Quarry, Brockley near Lesmahagow, High 
Blantyre, in Lanarkshire; Craigie (near Kilmarnock), Dockra 
(Beith), in Ayrshire. 
Calciferous Sandstone: Billow Ness, Fifeshire. 
