HATDEN.J MOEAINAL DEPOSITS. 53 



■vratch or east of the Park ranges. It is possible that a more detailed 

 study of the superficial deposits of this valley would afibrd reason, 

 for a separatiou into different periods so that they might be classified, 

 but my observations lead me to place them in one great period extend- 

 ing from the close of the Pliocene up to the present time. As is shown 

 by the map, the drift-deposits rest upon the granite directly, and no 

 sedimentary beds of any other age are found in the immediate valley, 

 and these deposits in the aggregate do not afford i)roof of any break in 

 time. Still much new matter could be added to the history of their 

 deposition if an entire season could be devoted to their study. 



