Heporta and Proceedings — Geolocjical Society of London. 141 



a fossil member of the Lycopodiacece, resembling in proportions and 

 outward morphology the existing representatives of the group. 

 The specimens described show stems, leaves, and sporangia whicli 

 appear to be borne laterally on the stem and to be embraced by the 

 bases of the leaves. Stomata do not appear to occur, and the 

 association of leaves of different types leads to the conclusion that 

 the three described species are in reality but one. The stems 

 consist mainly of long, thin-walled tubes covered with an epidermis 

 of long rectangular cells ; the leaves, in vertical section, show only 

 a single layer of complete cells. The absence of stomata and 

 cortical tissue may be explained, if the plant was submerged when 

 living ; but it is possible that the lower tissues of the leaf are lost, 

 together with any stomata which may have been present. 



2. " On the Origin of the Dunmail Raise (Lake District)." By 

 Eichard D. Oldham, Esq., F.G.S. 



The author considers that the gap through the Cumberland hills 

 is a natural feature whose remarkable character has not attracted 

 the attention which it deserves. In form it is an old river-valle}', 

 now occupied hy much smaller streams than that which formed it. 

 A windgap of this character cannot have been formed hy recession 

 of watersheds or capture through erosion, for in such a case the 

 stream on one side or the other of the watershed must necessarily 

 fit its valley, while in the Dunmail Raise there is a misfit on both 

 sides. The gap was in existence before the Glacial Period, and 

 consequently cannot have been formed by ice. So, by a process 

 of exclusion, the explanation is arrived at, which fits in with the 

 surface forms, that the gap of the Dunmail Raise was formed by 

 a river, which flowed across the hills from north to south, and cut 

 down its channel -pari passu with the elevation of the hills. The 

 final victory of upheaval over erosion, whereby this river was divided 

 into two separate drainage systems and the barrier of the Dunmail 

 Raise upheaved, may have synchronized with a diversion of the 

 head-waters and consequent diminution of volume and erosive 

 power. It is pointed out that this explanation comes into conflict 

 with previously published theories of the origin of the drainage 

 system of the Lake District, inasmuch as the elevation postulated 

 seems too slow to be explicable by the intrusion of a laccolite ; and 

 that the existence of a large river crossing the area of upheaval, 

 and the maintenance of its character as an antecedent river-valley 

 for a long period, show that the surface was originally a penei)lain 

 of subaerial denudation, and not a plain of marine sedimentation or 

 erosion. From this it follows tliat the course of the main drainage 

 valleys may not have been determined by the original uplift, but, 

 with the exception of those which are old river-valleys, whose 

 direction of flow has been reversed on the northern side of the 

 uplift, may have been formed by the cutting back by erosion into 

 the rising mass of high ground — in other wonls, that the principal 

 valleys of the Lake District may be subsequent, not consequent 

 in origin. 



