Vol. 69.] TRILOBITE EATJNA OF THE COMLEY BRECCIA-BED. 



3. The Trilobite Fauna of the Comley Breccia-Bed (Shropshire). 

 By Edgar Sterling Cobbold, F.Gr.S. (Read December 4th, 

 1912.) 



[Plates II & III.] 



Contents. 



Page 



I. Introduction 27 



II. Recapitulation of Previous Observations 27 



III. Description of the Trilobites 28 



IV. The Stratigraphical Horizon of the Breccia-Bed... 39 

 V. Inferences -JO 



VI. Conclusions 41 



I. Introduction. 



In a report to the Dundee Meeting of the British Association (1912) 

 upon the excavations made in the Cambrian rocks at Comley during 



1911, I called attention to a Paradoxides fauna, which appears to 

 be new to the district, and is found in the matrix of a remarkable 

 breccia near Comley Brook. 



The objects of the present paper are : — 



(1) To figure the trilobites of this breccia-bed, and to describe those species 



which appear to be new ; 



(2) To discuss the palceontological horizon in the Cambrian System which 



they indicate ; and 



(3) To consider some inferences that may be drawn from the occurrence of 



this fauna in its present position among the rocks of Comley. 



II. Recapitulation of Previous Observations. 



In order to make clear the special significance of the fossiliferous 

 Breccia-Bed, it is necessary to recapitulate some of the observations 

 already published. 



In the section of the Quarry Ridge, 1 the Groomii Fauna is found 

 in the matrix of a conglomeratic grit which rests upon the Lower 

 Cambrian limestones that yield the Protolenus-Callavia Fauna. 2 



A similar conglomeratic grit is found at Robin's Tump 3 with 

 some of the same fossils ; but in this case it rests, with visible 

 unconformity, on bedded green sandstones, which are regarded 

 as lower in the Cambrian sequence than the Protolenus-Callavia 

 Limestones. 



The conglomeratic nature of the grit is easily recognized, for the 

 matrix consists largely of rounded quartz-grains with a liberal 

 sprinkling of glauconite, and the included blocks are either pieces 



1 Eep. Brit. Assoc. 1908 (Dublin) 1909, pp. 234, 236: Excavations Nos. 1 & 2. 



2 E. S. Cobbold, Q. J. G. S. vol. Ixvii (1911) p. 297. 



3 Rep. Brit. Assoc. 1910 (Sheffield) 1911, p. 117 ; ibid. 1911 (Portsmouth) 



1912, p. Ill & fig. l,p. 112. 



