252 THE CANADIAN NATURALIST. [Vol. 



VI 1. 



two p:eolouical periods, but complicated by a simultaneous chancre 

 over the area in question from marine to estuarine and fresh- 

 water conditiouH. It seems certain that the formation of lignites 

 began in the Rocky Mountain region before the suit waters had 

 entirely left the area, and consequently while forms generally 

 known as Cretaceous were still living there. The evidence does 

 not ap|)ear to show that the Cret.iceous species were of them- 

 selves becoming rapidly extinct, but that over the Western 

 region, now forming part of this continent, the physical condi- 

 tions changing drove the Crctnceous marine animals to other- 

 regions, and it is impo'^r^ible at present to tell how long they 

 may have endured in oi .duic areas in other parts of the world. 

 This being so, and in view of the evidence of the preponderant 

 animal and vegetable forms, it seems reasonable to take the well 

 marked base of the Lignite series as that of the lowest Ten ary^ 

 at least at present. The formation described belongs to this 

 lowest Tertiary, being in fact an extension of Hayden's Fort 

 Union group, and from analogy may be called Eocfuc. Judging 

 froiM Hayden's descriptions this Northern extension would ap- 

 pear to be richer in lignite beds than that portion represented 

 on the Missouri lliver, and therefore to show a tendency in the 

 lignites to increa-o in importance northwards as they do south- 

 wards of that regi'U. 



NOTf] ON THE OCCUllRENCP] OF FORAMINIFERA,. 

 COCCOLITHS, &c., IN THE CRETACEOUS ROCKS 

 OF MANITOBA. 



I'.v a. M. Dawson, As. K. S. M., kc. 



A great portion of the Cretaceous division "in England and oa 

 the Continent of Europe, is composed of typical chalk, a sub- 

 stance which must have been formed in the tranquil depths of 

 the ocean, far removed from land, as it contains but a very 

 small proportion of any earthy impurity. It consists in great 

 part of the calc ireous shells of Foraminifera, and the still more 

 minute calcareous bodies known as Coccoliths. The remains of 

 the larger Molluscs and of Echiuodernis occur but rarely. The 

 American representative of this formation contains no beds of 

 true chalk, but is made up for the nio>-t part of deposits of sand 



