1G8 



THE GEOLOGIST. 



it is become impossible to procure it. At times the topaz is decomposed, and 

 then it is known under the name of " rotten topaz." 



The ores of tellurium are met with at Saint Joze d'Elrei, and near Saint 

 Yincent, between Ouro Preto and Morro Velho; moreover, there is some 

 native brimstone in a vein of quartz near Saint Joze. 



The crystalline schists of Morro Yelho and of Sabarra contain fine crystals 

 of carbonate of lime, of arragonite, of magnetic iron-pyrites, of copper-pyrites, 

 of manganese-ore ; in those of Congonhas there is chromate of lead. 



Arsenical pyrites are observed in the quartz at Ouro Preto, Morro Yelho, 

 and Antonio Pereira. 



Scorodite, pseudomorphs of hemonite after the scorodite, and scorodite after 

 arsenical iron, are found in the crystalline schist, and in the "tapanhoacanga" 

 of Passagem and Antonio Pereira. The amethyst forms in vems in the crys- 

 talline schist and in the gneiss. 



The chrysolite, cymophane, green and transparent tourmaline collect in the 

 cascalho of the rivers which traverse the crystalline schist near Kalihao. 



The American river and the Pianhy seem to be the richest ; the first is no 

 longer worked, but for twenty leagues along the road to Kalihao it seems to 

 have been entirely excavated; it is in the river Pianhy that the chrysolite is 

 found, which is employed in clock -making and in jewellery. The transparent 

 andalusite is also brought from one of these two rivers. Among the various 

 minerals that are found in the cascalho of Brazil, we can mention, as does also 

 M. Damour, disthene, felspar, precious garnet, hydrophosphate of aluminum, 

 phosphate of yttria, pure and titaniferous, diaspore columbite, Baierine, oxide 

 of pewter, cinnabar, and graphite. 



Gold is everywhere found in the region of the diamond-bearing schists, and 

 there is also platinum ; these metals remain upon the vatee with the other ores 

 that the washing separates, from the diamonds.— Translation of a Paper read 

 before the Geological Society of Berlin. By MM. Ch. Heusser and G. Clarez, 

 with mineralogical notes by G. Rose (Ann. des Mines, vol. xvii, part 2 of 1860. 



Silurian Strata, near Cardiff. — Dear Sir, — In your January number 

 there was a notice of " Murray's Handbook for South Wales." In the notice 

 of places of geologic interest appended to that book there is an omission I should 

 like to supply. A short time since I was residing at Cardiff, on the borders of 

 Glamorganshire, and in my walks about the neighbourhood discovered a quarry 

 in what seemed to me to be the Upper Silurian formation. This quarry is 

 situated on a hill-side about two miles east of Cardiff, at a place called Pen-y-lau, 

 and from the mouth of the quarry there is a beautiful view of the Bristol 

 Channel and the opposite coast. Tracing the course of some brooks in the 

 neighbourhood, I found the same kind of rock extended for some distance round 

 the side of the hill. The quarry I found to be very full of fossils. Shells were 

 in abundance. Amongst others I have a Bellerophon dilatatus, and an Athyiis 

 tumida, with Ihc internal spiral processes in a beautiful state of preservation. 

 ( lorals also Mere in abundance, though not so much so as shells and trilobites : 

 of the latter I found perfect specimens of Itttemis Barriensis, two kinds of 

 Acidaspis, Catymene Blumenbachii, Eucrinurus punctatus, Phacops caudatus, 

 Phacops ( caudatus) Leryi 3 and Phacops Stokesii, and a head and tail of Cheirurus 

 bimucronatus. 



I have also oui of ihc same quarry a large head of P//acops caudatus, in one 

 eye of which sixty two spherical lenses still remain. This specimen was pre- 

 sented fco me b\ Mr. .1. 1>. Thomas, of Cardiff, who is the only local geologist. 



Believing on the above evidence the rock in question to be Silurian, I was 

 surprised to find it mapped in t he Geological Ordnance Survey as Old Red 

 Sandstone. 1 therefore communicated the fact to Sir Roderick Murchison, 

 and at his request sent him my fossils, when after they had been examined by 



