FROM THE ROCKY MOUNTAINS. "^153 



a bruising and crushing action upon the fibres of the wood, this 

 action being obviotisly most intense near the periphery of the trunk. 



From a consideration, therefore, of all the facts of the case, we have 

 arrived at the conclusion that the specimen in question is a chip arti- 

 ficially cut by man from the tree prior to silicification. The grounds 

 which justify this conclusion may be summed up as follows : 1. The 

 specimen is a fragment of silicified wood, exhibiting definite and clean 

 surfaces cutting across the fibres of the wood. If these surfaces were 

 not artificially produced by some edge-tool, the agency by which they 

 were formed has yet to be pointed out. 2. The general form of the 

 fragment is precisely that of a chip cut by an axe. 3. The upper of 

 the two supposed cut surfaces is curved in the same way as is often 

 seen in modern chips when the axe has been blunt or has been loosely 

 held in the hand. 4. The lower surface (and less conspicuously the 

 upper surface also) exhibits numerous successive ledges or steps, such 

 as can commonly be observed in modern chips when the axe used has 

 been blunt, and which are due to the fact that the edge of the axe 

 has made a succession of slips in passing through the difiei-ent con- 

 centric layers of the wood. 



The chief objection which may be urged against this view of the 

 nature of this singular specimen is, that the surfaces of incision which 

 it exhibits are too clean and regular to liaA^e been made by anything 

 except a metal axe. It is to be remembered, however, that the wood 

 is obviously soft ; and that, in the second place, the pre-historic races 

 of ISTorth America were in possession of copper axes made from the 

 native copper of the Lake Superior region at a very early period. 



As to the age of the specimen, we can ofier no positive opinion. 

 It is possible that the specimen is much more modern than the silici- 

 fied forest in which it was found ; but we have been led to reject 

 this idea on the gj'ound of its complete identity in microscopic struc- 

 ture and chemical composition Avith the silicified trunks amongst 

 which it is found, and also on account of its very high degree of 

 mineralization. No hot springs occur at the present day in the 

 neighbourhood of the silicified forest where the specimen was dis- 

 covered, and similar petrified forests have been found in California 

 partially imbedded in stratified deposits of late Tertiary age. If our 

 conclusions, therefore, are correct, the specimen would lead us back 

 to a time when the giant Sequoias of the Sierra Nevada extended far 

 to the east of the Rocky Mountains ; but we have no data for fixing 

 ■even approximately the antiquity thus indicated. 



