THE 



GEOLOGICAL MAGAZINE, 



NEW SERIES. DECADE V. VOL. VI. 



No. III.— MARCH, 1909. 



0:EiX<3rXl<TJ^lL, -A.I?,TIOLE]S_ 



I. — A New Devonian Teilobite and Lamellibkanch from 



Cornwall. 



By Ivor Thomas, Ph.D., B.Sc, F.G.S. 



(By permission of the Director of the Geological Survey.) 



(PLATE III.) 



DURING the present survey of Cornwall Mr. Clement lleid has 

 discovered several interesting fossils which provide a substantial 

 addition to the previously recorded Devonian fauna of that part of the 

 country. The forms described below were found by Mrs. Clement Reid, 

 to whose patience and skill I am also indebted for the developing of 

 the best parts of the specimens. My best thanks are due to my 

 colleague Mr. H. H. Thomas for the accompanying drawings of the 

 two forms. 



Phacops {Trimcroceplialus) pcntops, sp. nov. (PI. Ill, Figs. 1-4.) 



Description. — The cephalon is obtusely round in front, with gentle 

 lateral curvature, slightly indented where the dorsal furrows bounding 

 the glabella reach the margin. The surface is covered with fine 

 granules of fairly equal distribution. The sub-marginal sulcus is well 

 marked, broader towards the front, and gradually diminishes in width 

 as it follows the narrow marginal border towards the genal extremities. 

 The length to breadth = 2:3. 



The glabella (PI. Ill, Fig. 2) is pentagonal in general outline, 

 tumid, protuberant, and overhanging at an angle of about 70° to 

 the plane of the dorsal surface. The length of the frontal lobe to 

 breadth = 3:4. The first pair of lateral furrows is not discernible ; 

 the second pair is seen faintly by strong magnification ; the third 

 lateral furrows are deep, and bound a well-defined basal lobe with 

 a small tubercle at each extremity. There are indications of a groove 

 across this lobe. The deep dorsal furrows separating the glabella from 

 the cheeks form an angle of about 81° with each other. The occipital 

 furrow is narrow and deep, with a fairly conspicuous and elevated 

 occipital ring, adorned by a tubercle at each end. 



The cheeh-areas are triangular, slightly tumid, and bounded towards 

 the margin of the head-shield by a narrow border, which is continued 

 under the overhanging frontal lobe of the glabella. 



DECADE V. VOL. A'l. — NO. III. 7 



