TUANSACTIONS OK SECTION (.'. 



723 



7, On til'' iiiipriiliuliilHif of thr throrij tliaf fiDniicr (IJacinl J'rn'iKJn in the 

 S"i'tlii'>'n llfmifplifrt' wirn iliw to Kccitntrifily nf ilio Earlli's Orinf, ami 

 to ltn Wintrr J'crikriii,,, in the XuiHi. Ihj W. F. Si.\xi.i,y, ¥.0.8., 

 F.R.Met.Soc. 



Tlio theory of Pr. Crnll, ncrcpted liy niaiiy pnilnjrists, is timl formtT jrlni'ial 

 iieriii'l'^ ill ill'' Xortiiern iii'iiiis|ilii'ii' wci'i- (liu- to ^ii'iiicr ••('(•ciiliicity ol' tlio I'liilh'.s 

 .irliit. ami to llii.-t li('miH|)ln'n' biinv at tin- tiiiio of ^.'laciutioii in wintiT ncrilu'lion. 

 Ihi.-i tliL'ory in 8up))ortt'il upon coinlitiiKis tliat iiic .-.tati'il to riilo approximalely at 

 tiie jire.'t'iit time 111 tin- Soiitlicrn ln'inisjiluMf, \vi)icli is assiimt'd to nc the cohler. 

 llcci'iit vi'soarcht's hy h't-rn-l and l>r. Ilann, with the aid of tcniiipratnn'ohscrvation.H 

 tiilii'H liy till) reci'iit'I'ian-^it of \'i'iMis('.\|)fdiiion.-'. Iiavrsiiown that tlionican tcinpcrn- 

 tiireiif the Soutlicrn hcniisplu'i'i' is tMjinil to, if not hi^rhfr ihan.tlio Xortlii'i'ii, thopro- 

 jinrtioiis hi'ini,' \61V. Sonlln'rn, l")-;J('. Xorlhfrii. 'I'lic conditions tlinl rnic in thu 

 Sdiitli at thi^ ])rcsent tinif an- a liniitiil iro/t-n area fthout the .Sontli I'oh-, not i>x- 

 tceilin;: thr sixtieth juvrallel of latitude; whereas in the North fro/en j.'n>und in 

 ceilaiii ilistricts, as in Siberia ami North-Western Canada, extends beyond tlui 

 lil'tit'tli paralltd ; therefore by conipiirison the North, as re^riirds the latitmlo in 

 wiiicli ( Ireiit Ilritain is situated, is at present the most (.dacialed lieniisphere. As 

 ii is very diHicult to eonceive that Iht! earth had at any former jjeriod a lower 

 initial temperature, or that the sun possessed less heat iiij.- power, glacial ion in tlio 

 North could never have depende<l upon the conditions ar;rued in Dr. Croll's theory. 

 Till' author sn<rL'esled that trlaciatioii within latitudes b.'tween 1(1° to (lU was pro- 

 lialily at all jieriods a local jilieiiomeiion (lependiii;r upon tho direction taken by 

 ai'vial nd oceaniir currents; as. for instance, (ireeidand is at jin.'stMit t;laciate(l, 

 Niirwny 1ms a mild climate in the samo latitude, the one beiii;.'' situated in the pre- 

 doiiiiiiatiiifr Northern Atlantic currents, the other in the Southern. ( 'ertain ]>liysical 

 rhaiiires brieliy sui^fjested in the distriliutiou of hind nii)jhl re\fr>e these conditions, 

 and render (ireeuland tlie wanner climati', Norwav thu cuMer. 



8. , . L-r.Ar,r Throri,:s\ 111/ the licY. E. IllU., M.A ., F.C.S. 



Oil the Montreal .Mountain, in tlie nei<rhi)onrin^'' ([uarries, nt the month of the 

 Sajrui'iiay Itiver, and morn or h'ss everywhere over all Canada and all t lie north 

 and north-west of tlii.s continent, are seen ])henomeiia wliich inijily a lormer vastly 

 <'\tPiuled action of ire. The like iire found over Murojie and Asia, thus comjilettdy 

 ciicirclinif the pole. Many theories have been propounded to account for these 

 farts. It ia proposed to pass tlu's;> liefore yon in review. 



Any explanation oiifrbt to account not only for cidd frrpater tlian the present, 

 li';t for accumulations of snow and ice. A jiindred phenoineniui is the i^reater size 

 of th(! Antarctic ice-cnj). The supposed inter).'lacial warm periods, and the nn- 

 i|ii('>tioiicd luxuriance of Miocene xe^rptation in (Ireeiiland, ou^ht also to liud their 

 causes in any thoron^rhly .satisfactory theory. 



The theories which have lieen ]iro])onn(led fall into tliree f.'ronps, as Cosmical, 

 Terrestrial, and Astronomical (or Feiiodieal). 



The Cosmical theories are I'oisson's Cohl-Space theriry — inconiprihensiblo; and 

 tilt' C<dd-San theory of S, V. Wood and otiiers lackiiii,'' any evidt^nce. 



The Terrestrial theories are numerous. Lyell's snirfrestion of I'ohir-continent 

 and Equatorial-ocean is opjiosed hy evidence tiiat continents and oceans lay on 

 much the same areas as now. Tiie conti'arv view, I'olar-ocean and l']qnatorial-lan(l, 

 Wduld desia've consideration lint for the same opjiosiiifr evidence. Tiie eh'vation 

 viinv (Dana, Wallace), which allefres fj-reater altitmle (d" mountain-chains, 

 •lisarrrees with the stromr evidence for land-depressi';n durinij- the period. The sub- 

 luerirence view of ])r. Dawson a^rrees with this evidence, but requires elucidation. 

 -Vlteration of ocean-currents ((iimn, .1. S. (iavdiner) is a most powerful a<rency,but 

 would net locally rather than universally roimd the pole. Alteration of ])revalent 

 winds, hitherto worked out by no one, deserves attentive consideration. Conditions 

 are conceivable which would produce over an area winds from cold quarters almost 



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