448 0. A. White — Puget Group of Washington Territory. 



nished no evidence upon this point. The invertebrate remains 

 which each formation has furnished afford no means of compar- 

 ison because those of the Puget Group are estuarine and those 

 of the Tejon Group marine : and because the estuarine types 

 of molluscan life are always of little if any value as indicating 

 geological age. Therefore we are reduced to stratigraphic evi- 

 dence alone in attempting to correlate the Puget, with the 

 Tejon 'Group. 



Mention has just been made of the discovery of strata con- 

 taining marine fossils at a locality on Dwamish river in Pnget 

 Sound basin, and not far from typical exposures of the Puget 

 Group. A considerable proportion of the fossils found there 

 have been identified with Tejon species, and those Dwamish 

 valley strata doubtless represent a part of the Tejon Group. 



Mr. Willis, who has studied the stratigraphy there in connec- 

 tion with his work before referred to, regards the position of 

 these marine strata with reference to those of the Pnget Group 

 as having been deposited not earlier than those of the upper 

 portion of that group. This view of the stratigraphical rela- 

 tions of the Dwamish river strata with those of the Puget 

 Group, together with the fact that the fossils of the former are 

 of marine origin, suggests that they were deposited in marine 

 waters towards the close of the great subsidence that accom- 

 panied the deposition of the Puget Group, and indicates that 

 the latter group is a local, although a large, chronological rep- 

 resentative of a part, or the whole, of the Chico-Tejon series.* 



Now if the strata of the Puget Group were deposited, even 

 in part, contemporaneously with the Chico-Tejon series, it is 

 probable that some of the species of that series which were capa- 

 ble of entering brackish waters may yet be found in the 

 Puget strata, and that some of the Paget fauna which were 

 capable of entering marine waters may yet be found associated 

 with Chico-Tejon species. As a matter of fact, however, no 

 evidence of such a commingling of the species of the two 

 faunas has yet been discovered. So far, therefore, we have no 

 paleontological evidence of the contemporaneity of the Puget 

 Group with the Chico-Tejon series. 



Although no serious doubt is entertained that the Puget 

 Group was deposited in estuarine waters there are certain facts 

 which are somewhat perplexing when considered in connection 

 with an acceptance of that view. The known area within 

 which strata of that group occur shows that the Puget estuary 

 was of such great extent that it is difficult to understand how 

 so large a body of water could have been uniformly kept so 



* It also seems to indicate that the western barrier of the Puget estuary was at 

 that time and place, not far from the middle of the present Puget Sound basin, 

 but it is probable that the position of the barrier was shifted from time to time, 

 during the existence of the estuary. 



