﻿Vol. 6 1.] THE SILURIAN ROCKS OF LLANGADOCK. 571 



the band, which is below the middle of the whorl, instead of being 

 submedian. As the specimen is very imperfect, it seems unadvisable 

 to assign to it a specific name, for it might possibly be a worn 

 example of an already described species, such as Bembeccia (?) 

 Lloydii, for instance. 



Dimensions. — The length of the fragment consisting of four 

 and a half whorls = 10 millimetres : the width of the penultimate 

 whorl = 6-5 mm. 



Horizon.— (90) Wenlock. 



Bembexia Lloydii? (Sow.). 



A fragment of a shell appears identical with this species. 



Dimensions. — The length of the fragment, consisting of about 

 six whorls, is 14 millimetres. 



Horizon. — (67a) Upper Ludlow. 



Etheridge gives the range of Pleurotomaria Lloydii as from the 

 Wenlock Shale to the Upper Ludlow inclusive. ' Murchisonia ' 

 sulcata, M'Coy, 1 which is identical with Pleurotomaria Lloydii, is 

 recorded from the Lower Llandovery. Lindstrom records its 

 occurrence in all the Silurian strata of Gothland. 



Family Mijrchisoniid^;, Koken. 

 Genus Goniostropha, (Ehlert. 

 Goniostropha Cambria, sp. nov. (PL XXXVII, fig. 6.) 



Diagnosis. — Shell very small, slender, turreted, composed of 

 more than ten whorls. Whorls increasing very gradually, angular 

 rather above the middle of the body- whorl, concave above, slightly 

 convex below. Surface smooth, no lines of growth being seen. 

 Band situated on the angle, grooved, and bounded on each side by 

 a strong raised thread. Base convex. Aperture imperfectly known, 

 subovoid. 



Eemarks and Resemblances. — There is only one specimen 

 of this species, but it is fairly well preserved, the grooved band 

 and contour of the whorls being clearly seen. It resembles Gonio- 

 stropha (?) elegans (Sollas), 2 from the Lower Wenlock of Rhymney, 

 but is much smaller, the band is proportionately more widely 

 grooved, the whorl less concave above, and it is also devoid of 

 the keels above and below the suture. 



Dimensions. — The single specimen consists of ten whorls, and 

 the apex is broken ; if it were intact, there would probably be 

 two or three more whorls. Length = 8 millimetres ; width 

 = 2-25 mm. 



Horizon. — (63) Lower Ludlow, Aymestry Limestone included. 



1 'Synopsis of the Silurian Fossils of Ireland' 1846, p. 17 & pi. i, fig. 20. 



2 Quart. Journ. Geol. Soc. vol. lviii (1902) p. 321 & pi. vii, figs. 2-4. 



