368 Reports and Proceedings — 



gulota and Serpulites fistula, above which follow the Shineton Shales, 

 and next, separated by a fault, the Hoar Edge grits (Lower Caradoc). 

 The author believes that the apparently conformable succession here 

 is due to parallel faults. Along the S.E. flank of the Wrekin the 

 quartz rock dips S.E., while the volcanic rocks dip N., and fragments 

 of the latter are contained in its base. The author is inclined to 

 think this a friction-breccia, and the junction a faulted one. He 

 also regards the junction with the Hollybush sandstones as a faulted 

 one, and maintains that in any case the quartzites are older than the 

 latter rocks, which are sometimes considered the equivalents of the 

 Ffestiniog group, and by Mr. Belt to be Menevian. The quartzites 

 can hardly belong to any part of the Upper Cambrian, and the 

 author passes on to consider the various positions which they may 

 be held to occupy, and gives reasons for thinking that they are Pre- 

 carabrian. The only fossil that has been found in them is a supposed 

 worm-burrow. In conclusion the author expresses the opinion that 

 the Stiper-stones quartzites are of Arenig age. 



2. " On the Affinities of the Mosasauridae, Gervais, as exemplified 

 in the Bony Structure of the Fore-fin." By Prof. Owen, C.B., F.K.S., 

 F.G.S., etc. 



In this paper the author commenced by discussing the opinions 

 ex^jressed by different anatomists as to the indications of relationship 

 furnished by the structure of the fore-limb, and stated that in 1851 

 he had referred Mosasaurus to a Tribe, Natantia, of the Order 

 Lacertilia. Since then Prof. 0. C. Marsh has published a recon- 

 struction of the fore-limb of the Mosasauroid Lestosaurus simus, and 

 from a comparison of his figure' with the bones of the same parts in 

 Cetacea, Plesiosauria, and Lacertilia, the author showed that the 

 resemblance in structure was closest with the last-named type, of 

 which the fore-foot of Monitor niloticus was taken for comparison. 

 In the relative length of the digits and the number and form of the 

 phalanges, the Mosasauroid fore-foot was shown to agree most nearly 

 with the Lacertilian type. With regard to the presence of a zygo- 

 sphene and zygantrum in vertebrge of Clidastes, cited by Prof. Cope 

 in favour of his approximation of the Mosasaurs to the Ophidia and 

 his establishment of the Order Pythonomorpha, the author remarked 

 that the trunk-vertebree of the Iguanidaa show zygosphene and 

 zygantrum, but with modifications which serve to distinguish the 

 Iguanian from the Ophidian vertebra3, and that until we have the 

 opportunity of comparing the Mosasauroid vertebrge with those of 

 both these types, the mere presence of these parts cannot be accepted 

 as conclusive. 



3. " On new Species of FrocolopTion from the Cape Colony, pre- 

 served in Dr. Grierson's Museum, Thornhill, Dumfriesshire ; with some 

 remarks on the Affinities of the Genus." By H. G. Seeley, Esq., 

 F.L.S., F.G.S., etc.. Professor of Geography in King's College, London. 



The species described by the author were named by him Froco- 

 lophon G'riersoni, P. spheniceps, and P. platyceps ; they are repre- 

 sented by skulls imbedded in a hard red ironstone matrix, apparently 

 concretionary, and were collected at Donybrook, Queenstown district, 

 Cape Colony. 



