EXPLANATION OF PLATE L L. 



1 PAL^OPORA SUBTILIS (M'^Coy). From Mulock quarry, Dalquorhan. natural size. 

 1 a Portion of do. magnified 12 diameters, the lamelliferous tubes projecting by weathering. 



1 h Small portion of do. magnified about 36 diameters. 



2 CYTHEROPSIS ALDENSIS (M-^Coy). From the limestone of Aldens, magnified 5 diameters, the 



upper figure a side view, the lower figure both valves seen from above , the line indicates the 

 natural size. 



3 HARPES PARVULUS (M'^Coy). Limestone of Wrae quarry, Upper Tweed, natural size. 



4 HEMITHYRIS SPHyEROIDALIS (M-^Coy). From the limestone of the Hollies, Church Stretton, 



natm-al size, profile. 



4 a Front view. 



4 h Entering valve. 



.5 HEMITHYRIS NASUTA (M-^Coy). From the limestone of Craig Head, natural size, profile. 



5 a Receiving valve. 



6 LINGULA OVATA (M-^Coy). From slates of Penmorfa, natural size. 



6 a Section about the middle. 



7 LINGULA DAVISII (M=Coy). Natural size, from slates S. of Penmorfa. 

 7 « Section of both valves about the middle. 



7 h Portion of surface and decorticated specimen, magnified. 



8 LINGULA TENUIGRANULATA (M<^Coy). From the schists of Alt yr Anker, Meifod, natural 



size of short valve, with dotted restoration of beak of large valve. 



S a View of beaks of both valves from another specimen. 



8 h Transverse section of both valves about the middle. 



8 c Longitudinal section of both valves, shewing the inequality of the beaks. 



8 d Surface magnified. 



9 ANODONTOPSIS SECURIFORMIS (M^Coy). Right valve, natural size, of elongate variety, from 



the Upper Ludlow rock of Benson Knot, Kendal. 

 9 a Left valve of shorter variety. 



10 DOLABRA ELLIPTICA (M-^Coy). Natural size, from the tUestone of Storm Hill, Llandeilo. 



10 a Profile. 



11 LEPTODOMUS GLOBULOSUS (M<^Coy). From the Upper Ludlow rock, near Kendal, natural 



size, left valve. 



11 « Profile. 



12 MACLUREA MACROMPHALA (M«Coy). From the limestone of Craig Head, natural size, 



viewed from above. 

 12 a Viewed from below. 



12 4 Profile. 



13 MACLUREA MAGNA (Leseur.) Natural size of rather small specimen, from the limestone of 



Aldens, shewing the top and form of the sections of the whorls and umbilicus. 



14 Small perfect specimen, viewed from below. 



15 ECCYLIOMPHALUS SCOTICUS (M^Coy). From the limestone of KnockdoUian quarry, natural 



size, under surface. 



15 a Another specimen, upper surface. 



15 J Section of whorl. 



