62 Mr David Forbes on the Chemical 



high-water mark. Whether it may have occurred, or been 

 going on, during the historic period, will probably be a 

 " vexata questio." It has been stated to me, on good autho- 

 tity that, about forty years ago, after a violent storm which 

 tore up large quantities of the submerged turf in Pooloash Bay, 

 some remains of buildings were observed between high and low 

 water. We venture to bring forward these few facts with the 

 view of affording a clue to the formation of the present con- 

 tour of the coasts of the Irish Sea, and of directing the atten- 

 tion of naturalists to the manner and period or periods in 

 which occurred the immigration into the British isles of plants 

 and animals, and also the manner in which the immigration 

 may have been stopped, renewed, and stopped again. 



On the Chemical Composition of some Norwegian Minerals. 

 By David Forbes, F.G.S., A.I.C.E. 



During a residence of many years in Norway I have availed 

 myself of the opportunity thereby afforded of studying the mi- 

 neralogy of several districts of that country, with special re- 

 ference to the circumstances under which the minerals occur- 

 red, and the causes which led to their appearance. 



In order to do this with effect, I found it necessary to enter 

 upon their chemical investigation, and it then became evident 

 that, the occurrence in these minerals of elements so rare as 

 to preclude chemists in general from studying their properties 

 with that precision which has been the case with most of the 

 other elementary bodies, involved the subject in much obscu- 

 rity, and before I could have confidence in the results obtained, 

 I was compelled to acquire some knowledge of the characters of 

 several bodies which had not previously come under my obser- 

 vation, as, for example, thorina, yttria, tantalum,* columbium,* 



# It must here be observed with reference to the names of tantalum and 

 columbium that the original nomenclature has been strictly adhered to in this 

 communication, tantalum being considered as the metal discovered by Eke- 

 berg in 1802, in the Kimitotantalite, whilst columbium was previously dis- 

 covered in 1801, by Hatchett, in the American columbite; this has since 

 been called niobium by Rose. — Vide Oonnell, London Philosophical Magazine, 

 1854, p. 461. 



