My original account of the mineral which I called Mordenite, from having first obtained it in the trap of the bay of Fundy, at Morden, King's Co., N.S., is to be found in the Journal of the Chemical Society, t864. A quotation is made from this to show the peculiarity of the deposit I am about to describe, and a few additions are given respecting opinions expressed on the species, and on its supposed occurrence elsewhere, before taking up the account of the recent observations to which I desire to draw attention.