486 



THE GEOLOGIST, 



PROCEEDINGS OF GEOLOGICAL SOCIETIES. 



Geglogical Society op London, November 2, 1859. — Prof. J. PliiHips 

 President, in the Chair. 

 The following comninnications were read . — 



1. " On the Passage-beds from the Upper Silurian Pocks into the Lower 

 Old Red Sandstone, at Ledbury, Herefordshire." By the Pev. W. S. 

 Symonds, P.G.S. 



In the cutting at the Ledbury Tmniel, on the Worcester and Hereford Pail- 

 way, a series of beds have been exposed, which range from the Upper Silurian 

 or Downton beds to the Old Ped sandstone, including bluish-grey rock with 

 fossil fish, crustaceans, and shells, like those found in the railway-cutting and 

 elsewhere near Ludlow. The followuig is the ascending order of the beds ob- 

 served : — 1. Aymestry rock, with Pentamerus Kfiu/ktii, &c. (ten feet). 2, 

 Upper Ludlow rock, with Cho?ietes lata, &c. (one hundred and forty feet. The 

 Ludlow Bone-bed seems to be wanting here). 3. Downton bedf, thin (nine 

 feet), with Lingula. 4 to 8. Ped and mottled marls and thin sandstone (two 

 hundred and ten feet), with Lingula and Pteraspis (?). 9. Grey shale and thin 

 grit (eight feet), with CepJialasjns and Pterygotus. 10 and 11. Purple shales 

 and thin sandstones (thu'ty-four feet). 13. Grey marl, passing into red and 

 grey marl and bluish-grey rock (twenty feet), with AucJienaspis, Plectrodus, 

 Cephalaspis (?), Onchus, PterygoUis Ludensis, Lingtda, and a Lituite (?). 

 These pass upwards conformably into a series of red marls, with yeUowish-grey 

 and pink sandstone, containing Pteraspis and Cephalaspis, and undoubtedly 

 forming the base of the Cornstone-series of the Old Ped Sandstone. The 

 author remarks that there are other cornstones, namely those of Wall-hills near 

 Ledbury, of Poxley, Writfield, &c., which are at least three thousand feet above 

 the Downton sandstone. He also remarks that, as the word " Tilestones" is 

 inapplicable to the Ledbury rocks, he quite agrees with Sir P. Murchison in 

 replacing it by the term " Passage-beds." 



2. "On the so-caUed Mud-volcanos of Turbaco, near Carthagena." By P. 

 Bernal, Esq. ; m a letter to Sir P. I. Murchison, P.G.S. 



Turbaco is a village, about fifteen miles from Carthagena, at an elevation of 

 about nine hundred and eighty feet above the sea. At a distance of about 

 three miles from the village, and at a higher elevation, in the midst ef a forest, 

 are some twenty or thirty conical hillocks, about eight or ten feet high, each 

 with its little crater or orifice, about two feet in diameter. These are fiUed 

 with a muddy water ; and every two or three minutes a slight noise is heard, a 

 bubbling up of air or gas takes place, the muddy fluid runs over, and forms into 

 cakes of blue clay. The water is quite cool, nor is there any present or 

 anterior marks or vestiges of the action of fire or heat. 



3. " On the Coal-formation at Auckland, New Zealand." By Henry Weeks, 

 Esq., communicated by the President. 



The district is formed of stratified sandy clays, of Tertiary age ; they vary in 

 colour from white to hght-red. The white clays contain beds of lignite, vary- 

 ing from a few inches to several feet in thickness. Sections of these beds are 

 exposed along the banks of most of the tidal inlets with which the district 

 abounds. In some places, near the hills, the lignite is seen to rest on trap- 

 rock ; elsewhere a shelly gravel underlies it. 



At Campbell's farm a whitish sandstone lies on the lignite, and at the junc- 



