162 ROYAL SOCIETY OF CANADA 



is derived from the fact that its borders and some part of its bed are 

 characterized by an abundance i>f submerged stumps and prostrate trunks 

 of trees, chiefly those of Pinus ponderosa. 1 was informed by Indians, in 

 1S7T, that some among them still living, could remember a time when 

 no lake existed in this part of the valley. " The lower end of the lake is 

 shallow and reedy, but is well rimmed round by bold mounds and 

 ridges of drift material on all sides but that now giving issue to the 

 stream, showing that no former channel in a ditferent direction is pos- 

 sible." The outlet had been slightly deepened ariiticially a few 3'ears 

 before the date of my first visit, at a time when the water (which is 

 employed for purposes of irrigation in the lower valley) had for some 

 reason ceased to flow. The existence of a ledge of hard rocks, however, 

 rendei"ed it im])ossible, without blasting, to deepen the outlet much. In 

 1890, I found, on again visiting the outlet, that an attempt had been made 

 to dam the lake, but had been abandoned, and the dam Avas completely 

 broken through. No evidence was found on either occasion of high- 

 water marks, other than slight traces such as might be accounted for by 

 annual seasonal changes, but in 1877 I satisfied myself that the existence 

 of an outlet to the lake was a comparatively recent event, by the follow- 

 ing observation : — •' A short distance beyond the actual outlet of the lake, 

 stumps of the ordinary yellow ])ine (P. ponderosa) are found in the bed 

 of the brook, where the circumstances render any diversion of the stream 

 impossible. This tree never grows in damp ground, far less with its 

 roots surrounded In' water, but is frequently I'ound on hill-sides, rooting 

 in the gullies down which a little water may run for a few days in the 

 spring. The valley now carrying the brook must have been of this 

 nature at the time the trees flourished, and this, in itself, would show either 

 that the lake did not exist at the time or that no water flowed from it. 

 The circumstances show that the natural diversion of the streams feeding 

 the lake is not po.ssible." 



In my report above cited, and dealing with this as an isolated case, 

 1 suggested that the ])ossible stoppage of some subterranean drainage- 

 channel might explain the existence of the lake ; but in view of the 

 facts since observed and in the absence of any proof of such a channel, 

 it now appears to me more probable that Stumj) Lake may be accepted 

 as another instance of a general change in climatic conditions. The 

 circumstances, it is true, are somewhat more complicated than those in the 

 cases previously cited, and it would also appear that, if thus explained, 

 the increase of humidity called for must date back to an earlier period by 

 many years than that necessitated by the other observations. 



While none of the facts here cited possess numerical accuracy, and 

 we are without such data as would allow of the satisfactory separation of 

 the ordinary annual seasonal changes in level from those of a secular 

 character, the general tenor of the evidence is sufficiently clear. It shows 



