Vol. 56.] FORMATION AND ITS GKAPTOLITE-FAUNA. 443 



is on the steep hill-slope above Frochas and the County Bridge (14). 

 The graptolites occur in hard micaceous flags, and the specimens 

 are much distorted and fragmentary, so that their identification is 

 uncertain. There is no doubt, however, that they belong to the 

 Monograptus-leintwardinensis type, but whether they belong to the 

 typical form or to the incipiens-yaxiety is dubious. 



(c) Confirmatory Sections. — Several other good sections of 

 the Lower Ludlow Beds occur farther west and south-west, and 

 the same general succession of rocks and fossils can be recognized 

 in each. One section, ranging from Dingle Mill to the County 

 Bridge, passes completely through the graptolite-bearing Lower 

 Ludlow Beds from the base of the M.-vulgaris zone to the top of 

 the zone of M. leintivardinensis var. incipiens nov. The M.-Nilssoni 

 bed is well shown at the Old Mill. (See fig. 8, p. 442.) 



Another complete section is visible in the stream from Trewern 

 Bridge to Ucheldre. I have not personally studied it in detail, but 

 I have examined the various graptolites collected from this section by 

 Prof. Watts, and the sequence is the same as in the Dingle-Mill 

 section. Along the road between Ucheldre and the County Bridge 

 the beds containing M. leintivardinensis var. incipiens are well exposed, 

 and at one locality (15) M. ultimus, Perner, is associated with it. 



Still farther south-west another section is exposed along the road 

 from Garbett's Hall to Black Bank. Here the beds immediately 

 succeeding the M.-vulgaris zone are relatively poor in graptolites. 

 I have, however, collected from them M. bohemicus, M. Nihsoni, 

 M. varians, M. uncinatus var. micropoma, and M. scanicus ? 



(d) Conclusions. — It is clear from the evidence afforded by the 

 sections exhibited on the northern side of the Long Mountain that 

 the Lower Ludlow formation here presents much the same general 

 palseontological features as in the Builth district. It shows, 

 nevertheless, certain peculiarities of its own. Firstly, the species 

 M. scanicus, so characteristic of a special pakeontological zone on 

 the Aberedw Hills, is practically absent : I have obtained, it is 

 true, one doubtful specimen from the Garbett's-Hall section. One 

 also occurs in Prof. Watts's collection, but the locality from which 

 it was obtained is unfortunately not certain. The species is, at all 

 events, extremely rare, and is useless, therefore, as a zonal fossil in 

 this district. Secondly, the typical M. leintivardinensis has not as 

 yet been found in this area, but its place would seem to be taken by 

 the incipiens-yaiiety. It is probable, however, that the horizon 

 marked by the typical form is here unfossiliferous, and that 

 M. leintivardinensis var. incipiens occupies a lower position in the 

 succession. Thirdly, two new forms, namely, M. uncinatus var. 

 orbatus and M. erinitus, are practically confined to this district, and 

 each of them has been detected at a single locality only. The first 

 of these graptolites has also been found in the Lower Ludlow Beds 

 of Dudley. 



With regard to the zonal divisions of the Lower Ludlow formation 



