374 MR. E. S. COBBOLD OX THE [vol. lxxvi, 



Upper Cambrian. 

 Horizon Ca. Orusia Shales. 



Acrothele coriacea. I Trilobite-fragments, suggesting one 



Orusia lenticularis. or more species of the Olenidae. 



Orusia lenticularis occurs plentifully in thin calcareous or mudstone-beds 

 intercalated with shales and, sporadically, in the shale itself. Prof J. C. 

 Moberg, writing 1 of the Orusia-lenticularis Beds of Sweden, says, 'not in- 

 frequently we find this brachiopod by itself crowding entire limestone-bands. 

 It occurs very often together with Parabolina spinulosa, especially in the 

 shales.' The conclusion that Horizon Ca should be grouped with the Upper 

 Cambrian seems fully borne out. 



Horizon Cx. 



This designation is used to include the beds which yielded ' Lingulella 

 nicholsoni and the Shineton graptolites ' to Dr. C. Callaway. 2 His exposure 

 has not been identified. It was situated some 500 yards, more or less, to the 

 north-east of Comley Quarry. 



X. GrEXERAL SUMMARY, 



As a result of this study of the Cambrian faunas of Comley, the 

 strata of the Lower Cambrian fall into eleven local divisions, Aa, 

 Ab,, Ah,, Ab 3 , Ab„ Ac, Ac.,, Ac 3 , Ac t , Ac 5 , and Ad. 



The first defined fauna to invade the area was one comparable 

 with, and in extension of, that found in the quartzite and 

 Hollybush Sandstone of the Malvern Cambrian area. From it the 

 genus Walcottina, intermediate between JSIickioitzia and Kutor- 

 gina, is now described. 



A second incoming fauna is possibly foreshadowed by a few 

 forms in Ab,, which include a species of Sol mi a or a near ally. 

 For want of brachiopoda and other fossils this fauna cannot he 

 closely defined. 



A third fauna] group, the Protolenus-Gallavia Fauna, appears in 

 Hoiizons Ac x , Ac.,, Ac 3 , Ac 4 , Ac.,, and includes a very considerable 

 number of species that find their analogues in the Lower Cambrian 

 •of North America. This group is separable into five faunas, not 

 necessarily of equal value, but sufficiently distinct to be worth}' of 

 separate record. The three lower faunas in horizons Ac,, Ac.,, Ac 3 

 .ai*e characterized by an abundance of fragments referable to 

 CaUavia callavei and other related species, and are sej:>arated by 

 the changes that are noted among the smaller trilobites, brachio- 

 pods, etc. The two higher faunas in horizons Ac 4 , Ac., are charac- 

 terized by plentiful remains of Strenuella in Ac 4 , and of Protolemis 

 in Ac 5 . Two genera among the pteropoda and one among the 

 gasteropoda are now described for the first time. 



Immediately above the Protolemis Limestone the Lcq)ivortliella 

 Limestone, horizon Ad, occurs : this appears to contain a fauna 



1 1910, p. 176. 



2 1877, p. 659. 



