92 



ROYAL SOCIETY OF CANADA 



are the most easily available as jfeologieal chroiioiueters. and have In'on 

 HO used both in Europe and America ; but they do not aceurately repre- 

 sent the series of ehangeu going on in the great oeeanie areas and their 



BSrt- 



Viewed in this way, Logan's name, Qnehec (iroup, designates the 

 oceanic deposits formed on tlie Atlantic border of Nortli Ameriea at u 

 time when very different conditions prevailed in those now inland areas 

 which afforded the elassitieation of the New York Survey. The fact of 

 this great ditlerence remains, and the tei'm designating it will continue to 

 be of value to geologists, so long as they are desirous rtuionaliy to corre- 

 late the sequence of formations in America and in iOuro^ic, and to connect 

 with their science those great facts of paheogeograjjiiy wliich enable us 

 to realize the diverse conditions of the deju'essed and ehjvated portions of 

 the earth's surface in diti'erent geological times. The name is fartlier 

 justified by the fact that the lower })()rtions of our great St. Lawrence 

 river follow a course in the Province of (Quebec wliich enables them bet- 

 ter than any other section in America to illustrate the diHerence between 

 the depo^■ s of the Atlantic and continental areas in the earl/ Paheozoic 

 period. 



I regard the.se consiilerations as of great importance in relation to 

 the fossils described in this paper, because they are members of a fauna 

 of almost univei'sal oceanic distribution ; in its time extending continu- 

 ously over vast spaces and periods, aiul serving to bridge over the gaps 

 in the broken series of the continental plateaus. It is likely to gain in 

 signiticance and in relative value as science advances; and, when more 

 fully known and appreciated, to do much toward reniedj'ing that imper- 

 fection of our geological record, which depends, to some extent, on our 

 basing it on localities where physical disturbances have interfered with 

 the continuity and orderly succession of life. It is only by the patient 

 and long-continued study of the formations deposited on those parts of 

 the permanent oceanic areas available to us, that we shall ultimately be 

 able to trace back the marine life discovered by the dredgings of the 

 •'Challenger," to early geological times. 



When Logan commenced his survey of Canada in 1842, little of this 

 was understood, and he had before iiim the task of solving the enigma of 

 original ditferences of deposits and suiierailded mechanical disturbances in 

 Eastern Canada, with the wholly inadequate key atlorded by the inland 

 aeries of formations worked out by the survey of New York, which itself, 

 when it came into contact with the marginal series, became involved 

 in that Taconic controversy, which has scarcely yet subsided, and which 

 must remain in some degree unsettled as long as geologists fail to see that 

 they cannot force into one system the dis.'<imilar formations of the ocean 

 and of the continental plateaus. 1 have no wish here to dwell on tliese 

 controversies ; but may refer for some statement of my views on the great 



