96 Me. J. Bhyce on Copper Ores in the Neighbourhood of Tarbet. 



under his own observation, and that of others, in which the motions of 

 the iris and the changes of adjustment appeared to proceed indepen- 

 dently of each other. 



The author further gave an account of the physiological evidence 

 in favom* of the view that the process of adjustment to near vision is 

 an active muscular change ; and he described the relation subsisting 

 between this process and the motions of the eye-ball, as well as the 

 influence exercised by the nerves over these motions. 



March 25, 1857. — The Phesident in the Chair. 



Mr. Robert H. Leadbetter, and Mr. Matthew Strang were elected 

 members. 



The following notices were brought forward by Mr. Bryce : — 1. " On 

 the Geological Relations of some Copper Deposits lately discovered near 

 East Tarbet." 2. " On some specimens of Iron, Copper, and other Ores, 

 from Nova Scotia and New Brunswick, with the products of their 

 manufacture ;" exhibited by Mr. Thomas Carswell. 3. " On some in- 

 teresting Mai'ine Fossils, lately found in a quarry within the city ;" 

 exhibited by Mr. Cohn Brown, Mi-. John M'Diarmid, and himself. 



I. On Some Coppee and Othee Metallic Oees eeom the 

 Neighbotjehood or Taebet on Loch Long. 



The ores in question occur on the estate of Erins, about four miles north 

 of Tarbet, and on the western shore of Loch Long. They are found 

 in veins traversing mica slate, which is the prevailing rock in this entire 

 district of country, quartz, always abundant in mica slate tracts, being 

 the chief matrix or veinstone of the ores. Copper pyrites is the most 

 abundant ore, and wide veins of it, obviously rich in metal, were traced, 

 in company with W. Furlong, Esq., proprietor of the estate, over a very 

 considerable extent, not less than two miles ; and they probably pass, in 

 their range to the S.W., into the adjoining properties. Other ores are 

 various oxides, yellow, green, and black copper, &c. In the same rock, 

 and adjoining these ores, ai'e also lead, with silver in unusually lai'ge 

 proportion, as shown by specimens assayed at the pubhc offices in 

 London. Beautiful specimens of zinc blende are also found, and can be 

 traced interruptedly in veins for some distance. While these and the 

 copper veins occur chiefly in the central and western part of the district, 

 the eastern affords extensive beds of haematitic iron ores. They occur 

 in ironshot mica slate, and in considerable beds on both sides of a moun- 

 tain stream, whose high banks they form through a distance of more 



