1859.] WEEKES COAL AT NEW ZEALAND. 197 



thin muddy marls over the Downton beds, which would have been 

 tilcstones had they sufficiently hardened, and which are doubtless 

 the equivalents of the true tilestones. 



I consider, therefore, the term "passage-rocks," as used by Sir 

 E. Murchison in the last edition of ' Siluria,' to be a more appropriate 

 appellation for these transition-beds, and one which allows to the 

 palaeontologist, as well as the physical geologist, a broad margin for 

 the line of demarcation between the two great epochs of the Silurian 

 and the Old Red. 



2. On the so-called Mtjd-volcanos of Tttebaco, near Carthagena. 

 By F. Bernal, Esq. 



[In a letter* to Sir E. I. Murchison, F.G.S.] 

 (Abstract.) 

 Tttebaco is a village, about fifteen miles from Carthagena, at an 

 elevation of about 980 feet above the sea. At a distance of about 

 three miles from the village, and at a rather higher elevation, in the 

 midst of a forest, are some twenty or thirty conical hillocks, about 

 8 or 10 feet high, each with its little crater or orifice, about 2 feet 

 in diameter. These are filled 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 hcatf . 



3. On the Coal-formation at Auckland, New Zealand. 

 By Henry AVeekes, Esq. 



[Communicated by the President.] 

 (Abstract.) 

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

 they vary in colour from white to light-red. The white clays con- 

 tain beds of lignite, varying from a few inches to several feet in 

 thickness. Sections of these beds are exposed alonic 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; else- 

 where a shelly gravel underlies it. 



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



the junction is hardened, and contains ironstone-nodules ; these, when 

 broken, yield remains of exogenous plants. A fossil resin is found 



abundantly in the lignito. On Farmer's Land the lignite is l(i I'eet 

 thick, including a little Bhale ; at Campbell's it is 7 feet thick, but thins 

 away. There is some iron-pyrites in the lignite, bul not sufficient 



to deteriorate its value as a coal. Similar mal has been found at 

 Muddy Creek to tbe S.W. ; at Mokail, about 1<>() miles to the south ; 

 ami near New Plymouth. 



* Dated British Consulate, Carthagena, New Granada, April '.', 1859. 

 t A sketoh of these salsee is given in Humboldt's '1 I ordillerae.' 



p 2 



