310 MR. E. S. COBBOLD ON TRILOBITES [Aug. I9II, 



Billingsella cobboldi, sp. nov. (See p. 305.) 



Fig. 20. Pedicle-valve [1112]: a, external cast; b, exterior from a plasticine 

 mould ; c, longitudinal section ; d, section of costge ; all X 2. 



21. Pedicle-valve [652] : a, posterior view of internal cast ; b, side view, 



restored about the umbo from a plasticine mould of the exterior; 

 both X 2. [The specimen has been somewhat damaged since the 

 figure was drawn.] 



22. Brachial valve [654 & 653] : external cast, X 2. 



23. Brachial valve, same individual [655] : internal cast, ribs somewhat 



damaged, X 2. 

 All the above brachiopoda are from the Shoot-Rough-Road Flags 

 and Sandstone, Comley. 



Orthis (Orusia) cf. lenticularis Wahlenberg. Shoot-Rough-Road 

 Shales, Cornley. (See p. 306.) 



Fig. 24. Brachial valve, internal cast [601], X 4. 



25. Pedicle-valve, external cast [614], X 4. 



26. Pedicle-valve showing larger dimensions, internal cast [611], X 4. 



Orthis ? sp. Shoot-Rough-Road Flags, Comley. (See p. 306,) 



Fig. 27. a, exterior, from a plasticine mould of the external cast of a very 

 'slightly convex valve, X 2 ; b, section of costas, X 5. 



Discussion. 



Dr. H. Lapwoeth, in expressing his sense of the value of the 

 paper, remarked on the general importance (from the economic 

 standpoint) of making trench-like excavations, such as those by 

 means of which the Author had conducted his patient and detailed 

 investigations. 



Mr. T. H. Withers said that the Author was to be congratulated 

 on having added a most valuable contribution to our knowledge of 

 the fauna and succession of the Middle Cambrian beds in the 

 neighbourhood of Comley. Perhaps the most interesting of the 

 trilobites obtained by the Author was the form named Dorypyge 

 laJcei, since representatives of the genus Dorypyge were also found 

 in the Middle Cambrian of North America, Bornholm (Baltic), and 

 China. ' Judging from the trilobite fauna described by the Author, 

 the speaker was of opinion that it showed closer affinity to that of 

 Bornholm than to that of North America, and he would be glad to 

 know whether the Author concurred in this view. 



Miss IUisin had been much interested in the paper, all the more 

 that owing to the kindness of the Author in sending her instruc- 

 tions she had been able to see a little of the sections described, 

 when she was recently in Shropshire on an expedition with her 

 students. She would like to ask a question with regard to the 

 section at Robin's Tump. It was evident that, in the southern 

 part, the limestone pebbles would belong to the grit laid down 

 after the interval of time marked by the unconformity. But what 

 exactly would be the position and age of the original limestone- 

 band the ' rib of limestone ' in the diagram ? It was extremely 



interesting to have an example of a limestone in these Cambrian 



