524 Reports and Proceedings — Geologists' Association. 



islands, or outliers from the main chain, and were conclusive evidence 

 that the Cotteswold range had extended as far as these hills did into 

 the vale, and that the horizontal valley running between the Cottes- 

 wolds and Churchdown, and the other outliers, with the transverse 

 valleys running between them, had all been caused by the wasting 

 denudation that had been , going on through vast periods of time. 

 Dr. Wright said he had purposely brought them to Churchdown to 

 give them one of the most telling lessons he could select to illustrate 

 the great truth that atmospheric agents supply the chisels by which 

 the solid rocks are sculptured, whilst rain, frost, and snow carry on 

 the work of destruction wherever they are exposed to these agencies. 

 Turning to the eastern view, the chain of the Cotteswolds pre- 

 sented a splendid picture, both as regards outline and colour, when 

 seen from the old rampart on which they stood ; and the Director 

 here pointed out the remarkable difference the opposite sides of the 

 valley presented, the angular summit of the Malverns finely con- 

 trasting with the rounded swelling summits of the Cotteswolds. A 

 long discussion now took place touching the various jDoints of 

 geological interest, and explanations and illustrations were asked 

 and fi'eely given. After visiting the church, the party returned to 

 the vicai-age, where the Rev. Mr. Smithe kindly refreshed the party 

 with hospitable cheer, and showed his collection of fossils from the 

 neighbouring hill. 



July 21st. — Leckhampton Hill was the object of this day's excur- 

 sion. The party assembled at the windlass at eleven o'clock, and then, 

 punctual to time, the Director of the day. Dr. Wright, F.R.S.E., 

 commenced his address. He had laid out on the grass several 

 large sections and maps of the hill, and proceeded to point out first 

 the connexion between the subjects referred to yesterday and those 

 which had to be studied to-day. 



He said the Oolitic system of rocks formed a most interesting study 

 both as regards structure, origin, and organic contents. The system 

 consisted of three great argillaceous formations, the Lias, the Oxford- 

 clay, the Kimmeridge-clay, and three sj^stems of Oolitic limestone 

 rocks superimposed on them — the Lower Oolite resting on the Lias, 

 the Middle Oolite on the Oxford-clay, and the Upper Oolite on the 

 Kimmeridge-clay. The great argillaceous deposits had been de- 

 posited under special relations, and the Oolite Limestone under 

 totally different conditions. The one had formed the shore of a wide 

 ocean ; the other was produced by the growth, decay, and recon- 

 struction of Coral Eeefs in the Jurassic Sea. In the argillaceous 

 seas sported the great Ichthyosauri, numerous fish, and Ammonites 

 in abundance; and in the Coral formations the Molluscs, Sea-urchins, 

 Corals, and Crinoids that lived in such localities, and have left 

 abundant remains in the limestone rocks, some beds of which are 

 composed entirely of organic remains. 



He described in detail the sands that lie between the Upper 

 Lias Clay and the Inferior Oolite, and which at Frocester Hill 

 contain a remarkable fossiliferous bed full of Ammonites and 

 Belemnites which were imperfectly represented here. Then the 



