274 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 25, 



shape of upright arched gateways. I may mention that fifteen miles 

 to the westward, at the foot of this same range, I found two hillocks 

 of quartz only twenty yards apart, with the strata dipping at exactly 

 the same angle of 40° to S.S.W., and therefore apparently quite 

 conformable ; but on close inspection the ends of the beds on the 

 inner side of one hillock were seen to be arched in such a manner, 

 as to show that they had been doubled on themselves, with the axis- 

 plane inclined at an angle of 40°. 



A wide undulatory district of slate and sandstone extends south- 

 ward of the main range ; but on the coast. Captain Sulivan again 

 found two east and west quartz ranges : one of these is transversely 

 intersected by a creek (near Port FitzRoy), and two good sections, 

 a hundred feet in height, are exposed. These are given in the fol- 

 lowing diagram on aecount of the complexity of the curvatures. 



almost resembling those produced by the mingling together of two 

 viscid fluids ; and because in crossing the country any one would be 

 apt to think that the dome-formed hills had been produced by single 

 impulses from below, whereas we now see that perpendicularly be- 

 neath one dome, another may lie hidden in the solid rock *. 



I will not take up the time of the Society by giving any further 

 details on the geology of these islands ; nor would the foregoing ac- 

 count have been worth communicating, had it not been for the in- 

 terest which is justly taken in ancient fossils coming from a very 

 distant quarter of the world. 



2. Description of Eight Species of Brachiopodous Shells from 

 tJie Paleozoic Rocks of the Falkland Islands. By John 

 Morris, Esq., F.G.S., and Daniel Sharpe, Esq., F.G.S. 



Plates X., XI. 



I. Chonetes Falklandica, sp. n. PI. X. fig. 4. — Transversely semi- 

 oval; upper valve convex, with a slight mesial depression; lower 

 valve rather concave ; surface covered with fine bifurcating rays 



* It is singular in how many points the old quartz-rock of Anglesea, as described 

 Dy Professor Henslow in his admirable paper in the Cambridge Phil. Trans, (vol. i. 

 p. 359) , agrees with that of the Falkland Islauds. The quartz of Anglesea is gra- 

 nulo-crystalline, and contains white earthy spots and a little mica; it passes insen- 

 sibly into an overlying chloritic schist, and this again into clay-slate. The strata 

 have been in a pasty condition, and have been singularly curved : they strike in 

 the same direction with the laminae of the overlying slates, but their average in- 

 clination is less. 



