73 



probably the number may have been greater, as the remainder of 

 the thorax and pygidium are wanting, the outer shelly covering 

 having disappeared, but the size and shape are indicated by a 

 smooth surface on the slate. The first segments of the pleurae 

 curve backwards at the extremities, and the curvature increases 

 towards the pygidium, until at the ninth segment it commences 

 one-tenth of an inch from the axis. This specimen, which is only 

 a cast or mould in the slate, approaches very nearly in general 

 form, size, and structure to Cybele ovata, the principal difference 

 being that our specimen shows no trace of the upward curve at 

 the extremities of the pleurae. 



Locality — summit of Skiddaw. The specimen was found by a 

 lady tourist, who having climbed to that elevation with much toil 

 and fatigue, wished to carry away some memento of her exploit, 

 and picked up a piece of slate for that purpose, near the base of 

 the pile of stones which marks the highest point. Looking at it 

 closely, she observed what she supposed to be a shell, and on 

 returning to Keswick, submitted it for examination to Mr. Birkett, 

 assistant-curator of the Museum of Local Natural History, and he 

 induced her to place it in the museum. The locality is within the 

 area over which the metamorphic action of the Skiddaw Granite 

 extends, and the slate contains numerous well-developed crystals 

 of chiastolite. , 



Group A. No. 2. 



This specimen consists of the impression of a large and very 

 beautiful trilobite, representing part of the left pleurae, axis, and 

 pygidium, in a fair state of preservation, but the remainder of the 

 body is partly imperfect, partly covered by overlying slate, and 

 partly obliterated. The thoracic portion of the axis is faintly 

 rounded, and measures an inch and nine-tenths in length, and an 

 inch and a half in width ; it appears to maintain its width to the 

 third segment, and then to taper rapidly towards the pygidium ; 

 the right axal furrow is partly covered, but the left is clearly 

 deiined. Body segments, eight, smooth and well-rounded; thoracic 

 portion of pleurae about half the width of axis, segments pointed 



