98 MK. H. LAPW0RTH ON THE [Feb. I9OO, 



An admirable section of tbe succeeding band may be examined 

 in tbe stream soutb of tbe Workhouse. A very f ossiferous set of 

 sbales at tbe first hedge above tbe road contains Monograptus 

 cyphus, M . revolutus(?) Kiirck., M. attenuatus, M. Sandersoni (?), 

 and CUmacograptus rectangularis. 



Of tbe higbest division — the Zone of Monograptus firn- 

 hriatus(Ac 3 ), little more can be said. Tbe limestone-bands of tbe 

 Wye section nave not been detected elsewhere. It is probable that 

 they thin out eastward and westward, and that they are of merely 

 local occurrence ; but with the information so far obtainable it is 

 impossible to say definitely whether this is the case. A tunnel on 

 tbe Birmingham Aqueduct, driven through the high ground above 

 Lower Downfield House, cut a complete section through the upper 

 shales (Ac 3 ). Only one fossiliferous zone in this tunnel, however, 

 was detected; and this proved to be a series of thin carbonaceous 

 banded grits containing small seams of iron-pyrites in the form of 

 diminutive globules — a characteristic of the shales yielding Mono- 

 graptus triangnlatus in the Wye section. In the grits occur 

 M. triangnlatus, M. gregarius (?), Diplograptus tamariscus, CUmaco- 

 graptus normalis, CI. rectangularis, and CI. plirygionius (?) Tornq. 



(4) Gigrin Mudstones. 



These are well shown in the lane leading to Ddol Farm, and 

 in the fir-copse below. The Birmingham pipe-trench runs through 

 this plantation ; and, when opened, showed an excellent section 

 which enabled me to obtain a fair idea of the rocks of the group. 



At the bottom of the copse the Calcareous-Nodule Beds 

 (Ad } ) are exposed. These were found to be overlain by about 

 60 feet of bard metallic- weathering, blue-banded, blue and grey 

 mudstones. Some of these blue bands are highly fossiliferous 

 and yield Monograptus convolutus, M. nuntius, Barr., M. lobiferus, 

 M. Nicoli, Harkn., 31. inopinus, Tornq., M. gemmatus(l) Barr., 

 M. crenularis, M. argutus, M. Proteus? Geinitz var., Diplograptus 

 bellulus, Tornq., D. tamariscus, CUmacograptus normalis, and CI. 

 undulatus. Ferro- manganese nodules are not uncommon ; and small 

 flat nodules of carbonate of lime also occur. The chief features 

 of the zone, however, are the blue bands and the dark-brown 

 metallic-weathering surfaces. The former gradually die out as we 

 ascend into our last zone (Ad A ), which is, unfortunately, to all 

 intents and purposes destitute of fossils. 



A good confirmatory exposure of these Gigrin Mudstones has 

 been excavated in the lane, and in the old quarries above Glan Elan. 

 From some blue-banded shale at the southern end of tbe lane 

 Monograptus lobiferus and M. Nicoli may be extracted. 



Identical rocks are exhibited in a small quarry about 100 yards 

 north-west of Gigrin Farm, with Monograptus convolutus, M. Proteus 

 var., M. crenularis, Diplograptus tamariscus, CUmacograptus nor- 

 malis, and CI. undulatus. 



Tbe relative hardness of this zone renders it exceedingly useful 



1 See C. Lapvforth, Geol. Mag. 1876, pi. xiii, fig. 4#. 



