88 SHELVE DISTRICT 



Discussion. The first Drabovia recorded in the British Isles is represented by a 

 small number of moulds (Tables 51-54) which compare closely with D. fascicostata 

 Havlicek (1950 : 47) from the Caradocian Letna Beds of Czechoslovakia. The 

 ribbing of the Shropshire specimens may prove to be finer and the pedicle valve more 

 convex but, provisionally at least, these differences are less important than the many 

 points of resemblance. 



Table 51 



Statistics of length (1) and maximum width (w) of 17 brachial valves of Drabovia cf. fascicostata 



Havlicek 



1 mm (var 1) 2-71 (1-192) 



w mm (var w) 3*71 (1-361) 



r 0956 



a (var a) 1-1068 (0-00647) 



Table 52 



Statistics of length (1) and maximum depth (th) of 7 pedicle valves of Drabovia cf. fascicostata 



Havlicek 



1 mm (var 1) 3-21 (1-231) 



th mm (var th) 1 -06 (0-069) 



r 0-988 



a (var a) 0-2375 (0-00028) 



Table 53 



Statistics of length (1) of 8 pedicle valves and the length of dental plates (dl) of Drabovia cf. 



fascicostata Havlicek 



1 mm (var 1) 3-47 (0-931) 



dl mm (var dl) 0-57 (0-043) 



r 0-837 



a (var a) 0-2161 (0-00233) 



Table 54 



Statistics of length (1) and the length of brachiophore bases (lc) in 8 brachial valves of Drabovia 



cf . fascicostata Havlicek. 



lmm (var 1) 3-52 (0-831) 



lc mm (var lc) 0-59 (0-015) 



r 0-820 



a (var a) 0-1367 (0-00102) 



NOCTURNIELLA Havlicek 1950 



Nocturniella sp. 



(PI. 14, figs. 17, 20) 



The internal mould (BB 35341) of a brachial valve, about 4 mm long and 4-5 mm 

 wide, is the only draboviinid so far recovered from the Mytton Flags -70 yds north 



