Charles E. Benhaon — Liquid Inclusions in Glass. 131 



Fifth Limestone. 



This limestone is fairly well exposed in the district. 



A small exposure occurs in the railway cutting leading to Longland's 

 mine, a quarter of a mile south-east of Woodend Station. The upper 

 light-coloured portion of this limestone is shown in the rai] cutting leading 

 into Glints Quarry. 



It can be seen in Ainsworth's Opencast near Cleator. 



A large but inaccessible quarry occurs at Yeathouse. 



The best exposure is at Stockhow Hall, half a inile south-west of Kirkland. 

 village, where there is a large disused quarry in both portions of this 

 limestone. 



A series of small quarries west of Scalesmoor Farm. 

 Sixth Limestone. 



Badly exposed, there being only two exposures, one a small quarry at 

 Stockhow Hall, the other a small exposure in railway cutting at Yeathouse 

 Quarry. 

 Seventh Limestone. 



The base of this limestone and its connexion with the Basement 

 Conglomerate can only be seen at one place in the district, viz. in the railway 

 cutting about 100 yards south-east of Yeathouse Station. There are two 

 good exposures of this limestone proi:)er, one at Frizington Park quarry 

 on the east side of the railway midway between Frizington and Yeat- 

 house Stations, the other at Moosegill Quarry, Wilton, about 2 miles east 

 of Egremont. 



Other exposures are at Thistlegill Quarry, 200 yards west of Kirkland 

 village ; Todholes Opencast, 100 yards north of St. Mary's R.C. Church, 

 Cleator ; a small quarry south of the Co-operative Society's old flour mill, 

 Cleator Moor ; and one or two small surface exposures near Scalesmoor 

 Farm, Lamplugh. 



Liquid Inclusions In Glass. 



By Charles E. Benham. 



TT is well known, that the liquid inclusions commonly found in 

 -*- quartz, fluor-spar, and other minerals resemble in some degree 

 those that occur in crystals of sodium chloride, alum, and many 

 salts. Chloride of sodium in particular shows innumerable cavities 

 of varying size, cubical in form (negative crystals), and generally 

 containing an enclosed bubble, especially if heated gently after the 

 crystals are formed. The smaller cavities show Brownian move- 

 ment of the enclosed bubble in a very striking manner. (See 

 Fig. 1, which gives a diagrammatic view of a salt crystal as seen 

 through the microscope.) 



Yet these cavities are evidently so different in origin from those 

 in such a material as quartz that they can hardly be classed as a 

 parallel phenomenon and they throw little light on the actual 

 problem of quartz inclusions, which are highly suggestive of an 

 origin connected with the enclosure within the mineral when molten 

 of aqueous vapour heated under pressure to a degree above the 

 " critical temperature ". 



Artificial inclusions which approximate perhaps rather more 

 closely to the cavities in minerals may also be obtained in resins 

 by boiling the resin in water, preferably tinted with a dye of some 

 sort or containing an infusion of gamboge particles. The melted 



