January, 1921] 



The Canadian FiELD-NATrRAi.isT. 



preceded by a rather prolonj^ed series of 

 masticatory movements involving both 

 mouth and throat, and in which the head 

 was nodded vi<^orously by movements in 

 the vertical plane, the downward ones being 

 the more vigorous. 



The enormous pectoral fins were used 

 in slow backward and fcrward locomotion, 

 each fin being kept in a vertical position 

 and slightly folded with the convex side 

 in the direction of movement. At rest 

 each fin is held out from the body almost 

 in the horizontal plane and against the 

 bottom, with the dorsal part posteriorly 

 placed and someAvhat raised. Rapid swim- 



ming is accomplished by undulatory move- 

 ments of the posterior part of the trunk 

 and tail ; the pectoral fins being extended 

 to the fullest extent and held horizontally 

 with the dorsal edge in front, while the 

 dorsal and anal fins are kept clo.se to the 

 body, at least anteriorly. 



Touching the side of the trunk or tail 

 resulted in the erection of the dorsal fin. 

 After repeated stimulation the response 

 became rather local, extending both for- 

 Avard and backwai'd from the level of the 

 point touched, but cliiefl\' backward. At 

 the same time the fiii was bent towai'd the 

 side stimulated. 



THE LIAKD RIVER FLOOD OF .JILV Hill). 

 By E. J. Whittaker. 



In a recent issue of the Geographical 

 Review • Dr. E. M. Kindle states that the 

 Liard is the main source of supply of drift- 

 wood for the Mackenzie River, and that 

 "the unusually high stage which the Liard 

 reached in 1919 set afloat a vast quantit}^ 

 of stranded logs, many of which had start- 

 ed their northern journey in previous 

 years." In view of tlie fact that this flood 

 was unprecedented within the memories of 

 the present inhabitants of the region, and 

 also that the writer was ascending the Liard 

 during the period of maximum flood con- 

 ditions, the following observations are pre- 

 sented wliich may be of interest to readers 

 of this publication. 



After a quick trip from Edmonton the 

 Geological Survey party to which the 

 Avriter was attached reached Fort Sim])- 

 son, N.W.T., on July 1st, 1919. This fort 

 is situated on an island at the junction of 

 the Liard and Mackenzie Rivers, and at no 

 other point is there a more striking vicAV 

 of the width and volume of this northern 

 waterway. Upon erujuir}^ we were told 

 that the flood stage of the river had reach- 

 ed its maximum about three days before, 

 and had now fallen four feet below the 

 high water mark. The following day, 

 Wednesday, July 2, we commenced track- 



'I'ublished by permission of the Director of 

 the Geological Survey of Canada. 



-Kindle, E. M., "Mackenzie River Drift- 

 wood", Geographical Review, Vol. XI, January, 

 1921, No. 1, pp. 50-53. 



ing up the Liard. Owing to the high 

 water, travel was not easy, yet we hoped 

 it would steadily improve as the river level 

 lowered. It did actually lower until Sat- 

 urday afternoon, July nth, during which 

 time Ave reached and passed the long series 

 of rapids about tiiirty miles above Fort 

 Simpson. We camped that evening on the 

 shore opposite the lower end of Gros Cap 

 Island, at tlie upper end of the canyon. 

 During the afternoon a slight increase in 

 the quantity of driftAvood Avarned us that 

 the river Avas once more rising. All day 

 Sunday it rose sIoavIv but steadily, ten 

 inches in the tAventy-four hours. 



About midnight of the 6tlh, the noise of 

 the water and the gi'inding and breaking 

 of trees increased perceptibly. The river 

 became (piickly covered Avith driftwood 

 from bank to bank and encroached rapidly 

 upon our camp site, Avhich had been se- 

 lected for convenience rather than Avith an 

 eye to floods. This site had to be abandon- 

 ed. As high ground Avas a long distance 

 back througli a dense forest and it Avas 

 noAv imjiossible to go upstream against the 

 driftAvood laden Avaters. which Avere already 

 undermining and drop])ing trees into the 

 river, Ave Avent carefully doAvnstream three 

 miles to Poi)lar river, Avhere a bank 250 ft. 

 high made certain that Ave could retreat as 

 high as necessary, and the dead Avater at 

 the moutli of the smaller stream made a 

 secure harbour for the canoe. 



We remained at this camp 4 da^s. dur- 



