xxiv Proceedings. {February 26th, ipoy. 



was blown into the lime basin, probably at Ardwick. The 

 particles of sand constituting the stone are extremely fine and 

 are aggregated by lime infiltration and the shapes of Encrinites 

 have been filled in with sparkling crystals. 



In ancient days Britain was celebrated for its tin and it is 

 thought that when British tin was first alloyed with the copper 

 of Cyprus it marked the commencement of the era of what is 

 known in History as the Bronze Age. We also know that the 

 Romans obtained pearls from the Conway Estuary, and there 

 can be little doubt that in their following they had geologists 

 to seek out the mineral wealth of the countries which they 

 conquered. 



It is interesting, therefore, to imagine some ancient 

 mineralogist picking up this curious stone, if only to see of what 

 these glistening crystals were composed, and leaving it beside the 

 vase in Roman Mancunium of which latter there can be little 

 reasonable doubt that it appertains to the Roman times in 

 Britain. 



Mr. Charles Oldham exhibited a melanic example of the 

 Brown rat (Mus decu7?ianus, Pallas), from County Wexford. 

 The black form of our common Brown Rat was, in 1837, 

 referred to a distinct species — M. hibernicus — by Thompson, the 

 Irish naturalist, who believed it to be allied to the Black Rat, 

 M. rattus, L. This opinion was not shared by Blasius and 

 other mammalogists, but much uncertainty obtained as to the 

 true affinities of the animal until the publication of a paper by 

 Messrs. Eagle Clarke and Barrett Hamilton in the Zoologist for 

 1 89 1. The authors showed conclusively that the so-called Irish 

 Rat was merely a melanic variety of M. decumanus. It is 

 subject to considerable variation; in many examples there is a 

 white spot on the chest, and the fur of the belly is sometimes 

 rusty brown in the median line. In the specimen exhibited 

 there were many silvery white hairs in the coal black fur of the 

 upper parts. The animal has a wide distribution in Ireland, is 

 found locally in the outer Hebrides and in^Norfolk and other 



