1867.] CLARK MATJEITmS. 185 



2. On the Geology of the Uppee Paet of tlie Yalley of tlie Teigis^, 

 Devoi^shiee. By G. Waeeln^g Oemeeod, Esq., M.A., F.G.S. 



[The publication of this paper is unavoidably deferred.] 



(Abstract.) 



The district noticed in this paper lies to the north of Bo'sey Tracey. 

 The author describes the courses of the Teign and its feeders, and 

 the strata traversed by those streams, namely, Granite and Carbo- 

 niferous Limestone. Gravels are occasionally found, which the 

 author regards as having been deposited before the reexcavation 

 of the valley ; and he shows that these had been transported by a 

 current from north-west to south-east. Prom the absence of these 

 gravels in the gorge of the Carboniferous rocks between Hunts Tor, 

 near Chagford, and Cliiford Bridge, he considers that that valley 

 has been opened since the time when the boulders and gravels were 

 deposited ; and he then shows that the stream from the valley of the 

 Teign, prior to the opening of that valley, passed by lEoreton Hamp- 

 gtead to Bovey Tracey. The paper contains notices of the minerals 

 found in the district, and of the Granite veins in the Carboniferous 

 rocks. 



3. Notes on the Geological eeattjees of Maueitiits. 

 By Geoege Claek, Esq. 



[Communicated by the Assistant-Secretary.] 



(Abridged.) 



Matjeititjs is weU known to be of volcanic origin, as is also the 

 neighbouring island of Reunion, where there exists a volcano in 

 constant activity. There is this great difference between the two 

 islands: Mauritius is surroimded by coral-reefs, which protect 

 nearly the whole of its coast, and by their shelter form excellent 

 harbours, while the coast of Eeunion is exposed to the full force of 

 the ocean. The action of the waves is so strong on its shores that 

 not a particle of the basaltic sand which strews them presents an 

 angle. Its beach exhibits nothing but a mass of pebbles, varyiug in 

 size from a foot or more in diameter to particles almost imper- 

 ceptible to the naked eye. 



The reefs of Mauritius support varions islets, which have been 

 generally regarded as forming an integral part of them, though 

 rising to as much as thirty feet above the sea-level. 



Gabriel Islet, is partly basaltic and partly calcareous ; and it is on 

 the latter that the late Dr. P. Ayres discovered the fossilized re- 

 mains of a forest, of which he gave an account at the Meeting of the 

 Eoyal Society of Arts and Sciences of Mauritius, in 1860. 



Egret Island stands on a calcareous bottom surronnded by sand 

 between the reef and the shore, about a mile from the former and 



