666 



with the Lacertlne or Squamate group. Amongst these may be no- 

 ticed, the predominance of the elongated form in the cranial bones, 

 extending from point to point with wide interspaces, and giving to 

 the osseous fabric of the head the appearance of a scaffolding ; the 

 posterior bifurcation, mesial crista, and foramen of the parietal bone ; 

 the form and relative position of the posterior frontals, and especially 

 the absence of the ridge which, in the Crocodile, extends like a second 

 zygoma longitudinally across the zygomatic cavity. Mr. Owen fur- 

 ther dwelt upon the form and position of the zygomatic portion of 

 the temporal bone, the bony interspace of the external nostrils, the 

 structure of the lower jaw, and particularly-on the existence of a wide 

 space on each side of the posterior region of the skull, bounded above 

 by the arch formed by the bifurcate processes of the parietal and the 

 tympanic bones, and opening into the temporal fossae, as evidences 

 of the affinity of the Plesiosaurus to the Lacertine Sauria. The cor- 

 respondence of the cranial organization oi thePlesiosaurus to those of 

 the Crocodile, was noticed in the strength of the maxillary apparatus, 

 the general form and structure of the upper jaw, and in the nature 

 and alveolar lodgement of the teeth. The peculiarities of structure 

 referable to the special exigencies of the extinct form of Saurian under 

 consideration, were also dwelt upon, and, lastly, those which charac- 

 terized the species described, and which illustrate its more imme- 

 diate affinities. 



April 25. — Egerton V. Vernon Harcourt, Esq., M.A., of Nuneham, 

 Oxfordshire ; George Crane, Esq., Ynyscedwyn Iron Works, near 

 Swansea ; Mr. James Tennant, Strand ; C. W. Grant, Esq., Capt. 

 Bombay Engineers ; and B. F. Outram, M.D., Hanover Square, were 

 elected Fellows of the Society. 



A paper was first read, entitled, "Notes on a small patch of Silurian 

 Rocks to the west of Abergele, on the north coast of Denbighshire ;" 

 by J. C. Bowman, Esq., and communicated by R. I. Murchison, 

 Esq., V.P.G.S. 



The author's attention was first directed to these strata by Mr. John 

 Price, of New College, Bristol. They occur immediately south of 

 the narrow belt of carboniferous limestone, which skirts the coast from 

 the Great Ormes Head, eastward, to the Point of Air and the Estuary 

 of the Dee. The belt of limestone is here not above a mile broad, 

 and the strata dip N. or N.E. At the base of the limestone precipices 

 at Craig y Forwyn, is a seam of impure coal about a foot thick, and a 

 thinner layer of bituminous shale with carbonized impressions of Le- 

 pidodendra? and a leaf-like Poacites. The beds constituting the 

 following section are successively displayed between Llandulas and 

 Garthewin, a distance of nearly six miles : — 



1 . Immediately under the limestone is a conglomerate, the basis 

 consisting of " light loam," and the rounded pebbles of 

 greenish, slightly micaceous sandstone, containing a few 

 bivalves and joints of encrinites. This stratum the author has 

 also seen between Llandeilo Bay and Colwyn on the Holy- 



