44 LOWER CAMBRIAN FOSSILS— WALCOTT. 



The species of Olenellus found in Shropshire, England, and given the 

 provisional name of O.callavei by Prof. Charles Lapworth,* is very closely 

 allied to, if not identical with, 0. broggeri. 



Nat. Mus. Oat. Invt. Foss., No. 18331. 



Avalonia gen. no v. 

 Avalonia manuelensis sp. nov. 



As the types of the genus and species are the same, one description 

 only will be given. 



The genus and species are founded on the central portions of the 

 head of a trilobite that differs from any described species knowu to me 

 in the form of the dorsal and ocular furrows and fixed cheek. 



Head, semicircular, moderately convex. Glabella, subquadrangular, 

 slightly convex, sides parallel; three pairs of narrow, shallow furrows 

 divide the glabella into four subequal lobes ; the two posterior furrows 

 extend about one third the distance across the glabella; the anterior 

 pair are very short and indistinct. Occipital ring narrow, transverse, 

 and separated from the glabella by a strong furrow. The dorsal fur- 

 rows are well-defined grooves, extending from the posterior margin to 

 the frontal rim. Fixed cheeks, broad, very slightly convex; the an- 

 terior fourth is separated by a narrow furrow that starts, at a slight 

 deflection, in the glabellar suture, and extends outward and backward 

 to the facial suture, where it passes into what, iu many of the trilobitt'S, 

 is the furrow or eye lobe. This furrow or groove occupies the posi- 

 tion of the ocular ridge, from the dorsal furrow to the facial suture, in 

 the genus Ptychoparia. The extension of the furrow backward joins 

 the one extending from the occipital furrow outward, just inside the 

 posterior margin. Frontal margin of medium width, and separated 

 from the glabella by a strong furrow ; posterior rim of head narrow, 

 rounded, and separated from the fixed cheek by a strong furrow that 

 unites at the postero lateral angle with the furrow on the outer edge of 

 the fixed cheek. The eye lobe is not distinctly shown in any of the 

 specimens. If present it is probably long and narrow, as in the genus 

 Centroplcura, of Augelin, or Anopolenus, of Salter. 



Free cheeks unknown. From the form of the fixed cheeks they were 

 evidently long and narrow. 



The brsad fixed cheek with its furrows on the lateral and posterior 

 margins recalls the cheek of Anopolenus, while the quadrangular gla- 

 bella is that of the genus Olenoides. As far as known to me the de- 

 pressed ocular furrow is peculiar to the genus. 



Formation and locality.— Lower Cambrian. In railway cut, 

 about 000 meters north of Manuel's Brook, Conception Bay, Newfound- 

 land. 



Nat. Mus. Cat. Invt. Foss., No. 18333. 



* Geol. Mag., new ser., Dec. Ill, vol. 5, 1868, p. 485. 



