1 



'iv :'h 



742 



repout — 1 884. 



!>. A incliminary Examination of the Silicious Organic Remains in the 

 Lacustrine iJcpn.nts of fJit Froci'uce of Nova Scotia, Canada. Bij 

 Alkxander Howard Mackay, 11. A., B.Sc. 



]\Iany oftlie lakes of Xova Scotia coutaiu large deposits aboundiiif!: i" these 

 remains which consist of the silicious skeletoi.B of upwards of sixty species ut' 

 diatumaceaj, and of the silicious spicules of atL'a..t ,' even species of fresh-water 

 spon<res. The deposits froni dillereiit lakes are gererally -niurked by a diil'crenoe iu 

 the species pres(ait or in their relative proportion. In lakes wliicli are not nfritated 

 by large streams bearing earthy sediments during tiuies of freshets, the deposits 

 generally consist of a light slimy brownish mud, sometimes of a depth hcvond 

 twenty feet, into wliicli a pole can be easily dri' en by the hand. This mud when 

 treated so as to eliminate the carbonaceous vegetable malter, leaves a variable per- 

 centage of exquisitely sculptured diatom cells and various forms of sponge spicides. 

 In some places tins percentage is very high and tlie deposit correspondingly whiter 

 and lirmer, in some eases consisting nearly of tl;e pure siliciouj valves and spicuk'S. 

 The diatomaceie grow not only in the -vaters of these lakes but in the streams 

 flowing into tliouj, so that these deposits are not all developed in situ. The spon|,'es, 

 on the other hand, ail'ect tlie stiller waters of the lake. They attach themselves to 

 and gruw upon portions ot submerged wood, stone or e\en sand, sometimes forminfr 

 extensive incrustations several iuclies in tluckness, some species extensively lobed 

 and even branching. Tlie sponge-ih^sh dying away each winter, innumerabk' 

 microscopic s])icula which formed its skeleton are tiius scattered in the waters, so 

 tlnit in some localities the sponge spicules form a greater proportion of the deposits 

 than the valves of the diatomacea'. 



8ome of tliese deposits may prove tn be of industrial importance, the material 

 being regarded as ca])able of use as polishing powder for various purjioses, aii;l in 

 the manufacture of dynamite. 



The lakes upon wiiich tliese pi'eliminary observations have been made incliule. 

 Ainslie, in Cape Ib-eton; Jjochalier, in Antigonish (,'o. ; Mackay, Black lirook, 

 Garden of Eden, Grant, M'Lean. Calder, Forbes, lien, and Toney Lakes in rietou 

 Co. : Mackintosh, bjarltown, and (TuUey lakes, in Colchester Co. ; the lakes wliieli 

 supply the city of Halifax with water, Grand Lake and Dartmouth Lake.s in 

 Halifax Co. ; and Kempt liake, in Kings Co. 



Lists of the species of diatomace.ie and spougidae detected in the several 

 deposits were givei, in the ])aper, which was accomptinied l)y microscopical slides 

 and specimens. The author has not yet concluded his researches. 



10. Tcvtli Report on the Circidatiov of UnJ err/round Watnrs in tlw Per- 

 meahle Formations of England and Wales, and the Quantltij ami 

 Character of the Water supplied to various Towns and Districts from 

 these Formations. — See Reports, p. 90. 



11. Fifth and last Report on Fossil Pohjzoa. — See Reports, p. 97. 



12. Report on the Exploration of the Raygill Fissure in Lothersdale, York- 

 shire. — Sec Reports, p. 240. 



WEDNESDAY, SEPTEMBER :?. 



The following Papers and Ileports were read : — 



1. The Geoloaical Age of the Acadian Fauna. Bi/ G. F. Matthew, yl.il/., 



F.R.S.G. 



Tn this sketch an attempt is made, by comparison with the Cambrian fauna of 

 other countries, and especially of Wales, to iix more exactly than has hitherto been 



