G. Sharman — New Species of Ole mis and Obolella. 565 



Dosthill (intrusive in Lower Silurian Shales). 



A fine-grained greenish- to greyish-brown crystalline rock. 



Under the microscope it is seen to consist of more or less imper- 

 fectly developed lath-shaped crystals of triclinic felspar, which, from 

 the extinction angles of some of them, appear to be labradorite, 

 octahedra and irregularly-shaped grains of magnetite, apatite and 

 pseudomorphs of serpentine, apparently after hornblende, since the 

 angles of some of these pseudomorphs correspond with the angle of 

 the oblique rhombic prism in hornblende. 



The rock may be regarded as an altered diorite. 



Appendix II. 

 IV. — On the New Species Olenvs Nuneatonensis and Obolella 



GRANULATA, FROM THE LoWEE SlLURIAN (' CAMBRIAN,' LaP- 



worth), near Nuneaton. 



By George Sharman, Esq. 

 Olenus Nuneatonensis, S., sp. nov. 



Locality. — West end of the Midland Eailway cutting, between 

 Nuneaton and Stockingford. 



Several fragmentary specimens of this Trilobite, differing in size, 

 yet exhibiting similar characters, have been collected from this locality. 

 The most perfect, although one of the smallest, is best fitted for 

 description. 



The length of this specimen is three-eighths of an inch, and the 

 head, or cephalic-shield, is rather more than one-third of the entire 

 length. The glabella is very convex, slightly narrowing in front, 

 but inflated and bending over the frontal margin. The neck-furrow 

 is distinct, the basal groove runs across the glabella, and there appear 

 to be two short indistinct furrows on each side. There are eleven to 

 thirteen body-rings, the pleurae of the 5th, 6th, and 7th bearing 

 short spines, and the 8th possessing a produced spine half as long 

 as the specimen itself, and projecting beyond the end of the tail. The 

 four terminal segments of the body also have spines, lessening in 

 length towards the tail. The tail is short, the axis showing it to be 

 composed of three, or perhaps more segments ; it narrows posteriorly, 

 and is subtruncate, being indented as in 0. micrurus. 



This species is distinguished from 0. micrurus by the more 

 lengthened spines from the posterior angles of the cheeks, and the 

 possession of those attached to the pleurae of the lower segments of 

 the body, the nearer approach and bending over of the glabella 

 towards the anterior margin, the continuance of the basal groove 

 across the glabella, and in the anterior portion of the body being 

 more parallel-sided. The character of the tail appears in all respects 

 to agree with that of 0. micrurus. 



It is distinguished from 0. bisalcatus, Phil., by the absence of the 

 mesial spine on the cephalic-shield. 



The marked difference in the size of these Trilobites (as before 

 mentioned) would undoubtedly suggest the probable presence of two 



