Reviews and Notices of Booh. 451 



statement that, at Tarapaca in Peru, the mineral is found in a 

 district supposed to be volcanic, and imbedded in the nitrate of 

 soda deposits. He then remarks that, with a very few excep- 

 tions, boracic acid is found ' either in directly volcanic regions, 

 most abundantly as such, or as borax : and a well-marked case 

 of actual sublimation of the acid from a volcano in the island of 

 Vulcano, near Sicily, has been studied by Warrington ; or in 

 smaller amount, in minerals the products of recent or extinct vol- 

 canoes, as Humboldtite from ejected blocks of Vesuvius, and zeo- 

 lites and datholite from trap of Salisbury Crags, New Jersey, and 

 other places ; or in minerals of purely plutonic or metamorphic 

 rocks, as tourmaline, the rhodozite of Roze, and axinite — the 

 species which contain it at all being few in number. It may be 

 noticed also, that traces of this acid have lately been met with in 

 the Kochbrunnen of Wiesbaden and in the waters of Aachen. 



*' If we may reason from the character of the majority of its 

 situations, we may almost consider the volcanic or at least igne- 

 ous origin of boracic acid so well established as to lead us, by its 

 occurrence in the gypsiferous strata, to seek for some volcanic 

 agency as the cause of their production. Such an origin has I 

 find already been assigned to the gypsum of Nova Scotia by Mr. 

 Dawson. This formation has been shown to be a member of the 

 Lower Carboniferous series, Jind is assumed to have arisen from 

 the action of rivers of sulphuric acid more or less dilute, such as 

 are known to exist in various parts of the world, issuing from 

 then active volcanoes and flowing over the calcareous reefs and 

 bed of the sea." ' 



" This is an interesting confirmation of the views formerly ex- 

 pressed as to the origin of the gypsum ; and though Professor 

 Hunt has ably shown, in his recent papers on Chemical Geology,* 

 that gypsum may be produced in stratified masses in aqueous 

 deposits by other processes, I am still inclined, in consequence of 

 the great thickness and local character of the deposits, and the 

 apparent absence of magnesian limestone, as well as the presence 

 of boracic acid, to adhere to the view above stated, in so far as 

 the great gypsum beds of Nova Scotia are concerned." 



The followinof are some of the results of Dr. Dawson's re- 



* Report of Canadian Survey for 1858 ; Canadian Naturalist ; Silli- 

 man's Journal, &c. 



