92 SHELVE DISTRICT 



Type horizon and locality. Spy Wood Grit exposed in north bank of Spy Wood 

 Brook, 170 yds north-east of Spy Wood Cottage (Grid Ref. SO 282958). 



Dalmanella salopiensis transversa sp. et subsp. nov. 



(Pi. 15, figs. 17-19, 21-24 ; Pi- 16, fig. 1) 



Diagnosis. Like Dalmanella salopiensis but with a brachial valve 73% as long 

 as wide and about one-tenth as deep as long ; dental plates 20% as long as the pedicle 

 valve and 192% in lateral extent as long ; subparallel brachiophore bases 22% as long 

 as the brachial valve. 



Type material. 



length width (mm) 



Holotype External and internal moulds of brachial valve 



(BB 35438a, b) 3-4 4-2 



Paratypes External and internal moulds of pedicle valve 



(BB 35439a, b) 3-5 



External and internal moulds of brachial valve 



(BB 35440a, b) 2-5 3-5 



External and internal moulds of pedicle valve 



(BB 3544ia, b) 2-5 3-0 



External and internal moulds of pedicle valve 



(BB 35442a, b) 2-5 3-2 



Type horizon and locality. Aldress Shales exposed in the bank of Ox Wood 

 Dingle at the south-west corner of Ox Wood, just north of the Rorrington-Wotherton 

 road (Grid Ref. SJ 290007). 



Discussion. Dalmanella is a common brachiopod in the Shelve successions. 

 Apart from a Dalmanella-like species from the Mytton Flags which has been sep- 

 arately described, the genus is represented by a series of closely related stocks with 

 small adult shells usually between 2 and 5 mm long ornamented by simply arranged 

 costellae numbering 6 per mm 2 mm antero-medially of the dorsal umbo, and bearing 

 a cardinal process with a small rounded myophore, well-developed subparallel 

 brachiophore bases and the impressions of a bilobed ventral muscle field. These 

 stocks occur in the Betton Beds to Aldress Shales inclusive but are very common in 

 the Meadowtown Beds, the Spy Wood Grit and the Aldress Shales which have 

 provided the data for the three samples listed in Tables 55 to 63. 



At first sight, the stocks appear to be like the Lower Llandeilo Dalmanella parva 

 Williams (1949 : 169) in the dimensions and proportions of their external and internal 

 features. However, a sample of that species from the type locality proved to be 

 significantly different from Shelve Dalmanella in a number of attributes. From all 

 three samples D. parva differs in the rate of anterior expansion and in the inherently 

 more acute divergence of its dental plates. The species further differs from the 

 Meadowtown and Spy Wood forms in the relatively faster growth in width and, from 



