DESCRIPTION OF THE FOSSILS. 
221 
S. papilionacea. Ph. PI. XI. fig. 6. Bolland ; Otterburn. 
Extremely wide, semielliptical, with very fine rather bent radiating striae ; in young 
specimens the striae are beautifully crenulated. 
Orbicula nitida. Ph. PI. XI. fig. 10, 11, 12, 13. Bowes; Pateley 
bridge ; Lee, Harelaw, and Otterburn ; Coalbrookdale. 
Oval, glabrous, finely radiated ; lower valve flat, upper conico-lenticular, apex near 
the narrower end. The Coalbrookdale specimens are slightly more depressed than 
those of Yorkshire and Northumberland. 
Lingula squamiformis. Ph. PI. XI. fig. 14. Bolland. 
Oblong with parallel sides ; truncate in front, acuminated retrally ; a central oblong 
depression ; surface with finely radiating and concentric lines. It does not quite agree 
with L. mytilloides of Sowerby. 
L. elliptica. Ph. PI. XI. fig. 15. Ashford in Derbyshire. 
Long elliptical, acuminated retrally ; surface with delicate radiating and concen- 
tric lines. 
L. marginata Ph. PI. XI. fig. 16. Bowes. 
Very oblong, with parallel sides, truncate in front, rounded retrally, edge of the 
valves turned up ; slight mesial ridge on a flat space ; small oval hollow, fine radiating 
and concentric lines. 
L. parallela. Ph. PI. XI. fig. 17 — 19. Northumberland. 
Magnified views of a species which seems different from the last, by its rounded 
front, and equally convex surface. 19, flatter valve, 17, 18, deeper valve. 
Terebratula. Div. 1. — Smooth, generally oblong ; the middle of 
the front even or depressed. 
T. hastata. Sow. PI. XII. fig. 1. Derbyshire ; Otterburn ; Bolland; 
Queen’s County. 
Depressed, valves plane or plano-sulcate in the middle, with (irregular) radiating 
striae. Outline variable, from pentagonal to ovato-trigonal. 
T. saceulus. Mart. Sow. PI. XII. fig. 2. Bolland ; Greenliow hill ; 
Kirby Lonsdale ; Orton ; Northumberland. 
Gibbous, valves sulcate, or plano-sulcate in the middle ; front emarginate, obtuse. 
T. pentaedra. Ph. PI. XII. fig. 3. Bolland ; Orton. 
Pentagonal, depressed, surface undulated, front and sides emarginate, perforation of 
the beak minute. 
T. ambigua. Ph. (Spirifera Sow.) PI. XI. fig- 21. Northumber- 
land. 
Pentagonal, front deeply undulated, beak with a large round aperture. 
F f 2 
