394 Vorks/iirc Xdfiinilisfs at Gnisborough. 



stones and paviiii^ setts, the members had an excellent oppor- 

 tunity of examhiing its chief features. Passing- along a deeply 

 excavated trench, it could be seen that it consisted of a crystalline 

 rock, bluish in colour and conchoidal in fracture ; hard, and of 

 close, fine texture. Remarkably little disturbance of the strata 

 has been caused by the intrusion of this vast body of molten 

 mineral, which here reaches a thickness of about 80 feet at the 

 depth to which quarrying operations have been carried. In 

 Gribdale quarries, where the stone is mined, candles were 

 provided by the owners, and the workings were explored for 

 several hundreds of yards. 



The intrusion of the hot mass could be seen to have con- 

 siderably changed the character of the Jurrassic rocks with 

 which it came into contact ; and in the open workings it was 

 noticed that occasionally in the softer shales lines of cleavage 

 had been formed perpendicular to the bedding planes. The 

 analysis of the basalt as given by Mr. J. K. Stead is as follows : — 



Silica... ... ... ... 59. 25 per cent. 



Alumina ... ... ... 16.75 " 



Ferric Oxide ... ... ... 4.00 ,, 



Ferrous Oxide ... ... ... 4.82 ,, 



Lime 6.88 



Magnesia ... ... ... ... 3.81 ,, 



Potash ... ... .. ... 1.92 ,, 



Soda... ... ... .. ... 2.56 ,, 



On the way from Highcliffe to Roseberry Topping the effect 

 of Glacial action and the damming back of melted ice and 

 subsequent cutting of overflow channels could be well seen in 

 Sleddale. 



A considerable number of erratics was noticed, and much 

 morainic matter seen at near the 1000 feet contour, which raises 

 doubt as to the correctness of the generally accepted opinion 

 that the ice barrier did not in this district rise to a height of more 

 than 800 feet above sea level. 



From an industrial point of view the Cleveland Ironstone 

 seam is the most important geological feature, and this, by the 

 coiu-tes}' of the owners of Spawood Mines and the aid of the 

 manager, Mr. W. Charlton, and his son, was examined, and 

 much information as to its nature and occiurence was gathered. 



Vektichk.vtic Zoologv. — .\ toad ^liiifo v///gt/n's) was observed 

 by the mycologists in Waterfall Wood. 



Naturalist, 



