480 J. E. MARE AND T. KOBEETS ON THE 



shales are seen in a lane north of the church, dipping north, and 

 they are very flaggy and calcareous towards the summit, but lime- 

 stone bands do not occur as in the above localities. 



The section seen in this lane, and in a quarry immediately 

 to the east of it, is shown in PL XY. fig. 4. 



6. Trinucleus-seticornis Beds. — These are subdivided into three 

 stages, viz. : — 



(a) Sholeshook limestone. 



(6) Eedhill shales. 



(c) Slade calcareous shales. 



The beds succeeding the Eobeston TTathen limestone consist 

 mainly of blue-grey shales, weathering olive-green, with a con- 

 siderable development of calcareous matter at the base and summit. 



The form Trinudeus seticornis, or its variety BucMandi, occurs 

 throughout, and is very characteristic of these beds, which may 

 therefore be spoken of as the Trinucleus-seticornis beds. 



(a) Sholeshook Limestone. — At Eobeston Wathen, the central 

 part of the quarry, as shown in the section (fig. 3), contains the 

 upper portion of these beds immediately succeeding the Eobeston 

 Wathen limestone. It differs considerably from that limestone both 

 lithologically and palseontologically. Whereas the black limestone 

 is evidently a calcareous development of the black shales, the 

 calcareous band we are now considering is no less clearly a 

 member of the blue-grey shales ; and this is also true of the lower 

 zones which occur in other localities. The following fossils occurred 

 in this calcareous band : — Heliolites interstinctus, Wahl., Glyijtocrinus 

 hascdis, M'Coy, Trinudeus seticornis, His., Phacops Brongniarti, 

 Portl., P. alifrons ?, Holojoella, Orthoceras. 



The actual limestone appears to have been crushed out at this 

 point, the fossils occurring in calcareous shales which are elsewhere 

 seen immediately above the limestone itself. 



Confirmatory Sections. — At Prendergast, as seen in fig. 4, the 

 uppermost member of the Orthis argentea beds, which is there 

 calcareous, is succeeded by greenish, impure limestone, crowded with 

 fossils, especially trilobites, although the limestone itself is much 

 crushed. The fossils are similar to those of Eobeston Wathen, but 

 are much more abundant. The following occur : — 



Homalonotus ? 



Trinudeus seticornis, rar. BucHandi, 



Barr. 

 Agnostus trinodus, Salt. 

 Orthis elegantula, Balm. 

 Leptsena quinquecostata, M'Coy. 



sericea, Sow. 



tenuicincta, M'Coy. 



Strophomena rhomboidahs, WilcJc. 



Ctenodonta ? 



Bellerophon bilobatus, Sow. 



Orthoceras, 



Cyrtoceras sonax, Salt. 



Halysites catennlarius, 



Petraia, 



Crinoid and cystoid fragments. 



Tentaculites anglicus, Salt. 



Phacops mucronatus, Brongn., var. 



alifrons, Salt. ? 



Cheirurus bimucronatus, Murch. 



juvenis. Salt. 



octolobatus, M'Coy. 



Lichas laxatus, M' Coy. 



Stygina- 



Cybele verrucosa. Balm. 



lUgenus Bowmanni, Salt. 



At Sholeshook a splendid section is exposed in the railway- 



