Geological Society. 483 



GEOLOGICAL SOCIETY. 



[Continued from p. 404.J 



March 10, 1858.— Prof. Phillips, President, in the Chair. 



The following communication was read : — 



" On the Gold-diggings at Ballaarat." By H. Rosales, Esq. (In 

 a letter to W. W. Smyth, Esq., Sec. G.S.) 



"By the aid of machinery, and through the alteration of the mining 

 regulations granting extended claims, the old ground has been pro- 

 fitably re-worked ; and, by the introduction of the frontage-system, 

 which, according to the difficulties to be overcome, grants extensive 

 claims on new ground, the present ' leads,' most of which are N.W. 

 of the Gravel Pits, under the townships, are advantageously worked. 

 The amalgamation of three or more claims is also allowed, the miners 

 having then to put do\vn only one shaft. 



" The engines most in use are stationarj', of from 15 to 20 horse- 

 power, with winding and reversing gear. To the end of the wind- 

 ing-gear-shaft is attached the crank for the pump, and the motion 

 is also taken to drive a puddling machine, which is nothing but the 

 arrastra working without mercury. The depth of sinking averages 

 about 300 feet, of which in some instances there are as much as 

 200 of basalt to be cut through. 



"At the junctions of the Frenchman's and White Horse Leads, in 

 the Eldorado, the remains of a tree were found in an undisturbed 

 position, with the roots fast in the wash-dirt ; and it might be 

 interesting to you to know that at Poverty Point the deep channel, 

 with a N.W. strike, is crossed at about 140 feet higher by the 

 shallow channel, which has a strike of N.E. by E., and which again, 

 in its turn, is crossed, at a level of 20 or 30 feet still higher, by the 

 present water-course, the strike of which is W." 



March 24. — Prof. Phillips, President, in the Chair. 



The following communications were read : — 



1. " On a protrusion of SUurian Rock in the North of Ayrshire." 

 By J. C. Moore, Esq., F.R.S.. F.G.S. 



The author described the coast-section of a part of North Ayr, 

 from Ardrossan to Goldenberry Hill, north of Portencross Castle, 

 altogether about five miles in length ; and he showed that the red 

 sandstones (of Devonian age) that succeeded the coal-measures of 

 Ardrossan, from which they are cut off by a trap-dyke, dip sputh- 

 WEirdly for upwards of two miles, then form a low anticlinal, and are 

 then vertical for a short distance ; after which they are abruptly 

 succeeded by a contorted and arched mass of purple, green, and 

 black schists of Silurian age. The schists are immediately succeeded 

 on the north by unconformable red sandstones and conglomerates, 

 dipping northward, cut through by greenstone, and apparently be- 

 longing to a lower stage than that of the red sandstones on the south 

 of the axis ; sandstones similar to the latter succeed, with a conform- 

 able dip, and arc traversed by a porphyry which forms a massive cover- 

 ing above them, and constitutes the picturesque hill of Goldenberry. 



The author remarked that an axis of elevation has disturbed the 

 Old Red sandstone, Coal-measures, and Permian sandstone in the 



