392 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



plant remains. The beds containing the plant remains are prac- 

 tically undisturbed, having but a very slight dip to the east (gen- 

 eral direction). The sediments were, clearly, deposited in stand- 

 ing water and are evenly and finely bedded. The conglomerate 

 below the fossiliferous beds is made up of worn and sorted 

 cobbles and cemented to a large extent with iron. 



There is no field evidence to show the interglacial age of the 

 plant-bearing beds. I may say that I have found no fossils in 

 the glacial deposits along the Kocky Mountain trench in the 

 region from Cranbrook to Golden. The glacial silts were ap- 

 parently deposited by lateral, glacial streams emptying into a 

 lake occupying the trench, upon the retreat of the ice. It does 

 not seem probable that climatic conditions would have been 

 favorable for a warm climate flora to flourish in isolated areas 

 in the trench when glacial action was undoubtedlj' very active 

 in the bordering mountains. 



I trust this information Avill help to clear up the age of the 



beds under discussion. r . jn x tti 



[signed] John i . W alker. 



In his communication, transmitting the above memorandum. 

 Doctor Kindle remarked: '*Mr. Johnston has the impression 

 that the plant-bearing beds are of late Tertiary age. However 

 that may be, the memorandum by Walker at least indicates their 

 relationship to the only glacial deposits which have actually 

 been seen in the area where the plants are found, and suggests 

 that the base of the Pleistocene and the top of the St. Eugene 

 silts should be drawn at the bottom of division F (see p. 393) of 

 Schofield's section." 



In order that the above stratigraphic references may be more 

 clearly understood I have thought it advisable to quote from 

 Doctor Schofield's Memoir (op. cit., pp. 85-87, 90-91) certain 

 paragraphs descriptive of the geology, as follows : 



' ' The greater jsart of the Cranbrook map-area is covered with drift, especially 

 the Eocky Mountain trench and the valley of Gold Creek. Prom their character 

 and distribution, the records are interpreted as belonging to two glacial periods 

 separated by a period of glacial retreat. The interglacial deposits are remarkable 

 for their content of a flora whose modern representatives are indigenous to a climate 

 warmer than that of the southern United States. The deposits, Pleistocene and 

 Recent, can be subdivided as follows: 



