88 PROCEEDINGS OF THE PHILADELPHIA MEETING 



(Algoman Granite and Gneiss.) 



Laurentian of some authors, and the Lorrain granite of Cobalt, and 

 the Killarney granite of Lake Huron, etc. 

 Igneous contact. 



TiMISKAMIAN. 



In this group the authors place sedimentary rocks of various localities 

 that heretofore have been called Huronian and the Sudbury series 

 of Coleman. 

 Great unconformity. 



There is no evidence that this unconformity is of lesser magnitude 

 than that beneath the Animikean. 

 (Laurentian Gbanite and Gneiss.) 



Igneous contact. 

 Loganian. 



Grenville (sedimentary), Keewatin (igneous). 



The authors have found the Keewatin to occur in considerable volume 

 in southeast Ontario and have determined the relations of the 

 Grenville to it. 



Investigations by the junior author during 1914 have shown that certain 

 rocks of the "classic" Huronian area of Lake Huron, the "Thessalon green- 

 stones," that heretofore have been placed with the Keewatin, are of much 

 later age, being in intrusive contact with the Animikean, as defined in the 

 above table. 



Presented in abstract extemporaneously by the senior author. 



Discussion 



Prof. H. P. CusHi.xG stated that the proposed classification was easily ap- 

 plicable in the Adirondacks, and that he had for some time felt that the 

 Grenville was most probably to be correlated with the Keewatin. because of 

 its similar relationship to the oldest granite invasion, the Laurentian. That, 

 in Professor Cushing's opinion, in pre-Cambrian correlations the wide-spread 

 intrusions furnish the safest guide ; that in all likelihood the later intrusive 

 masses of the Adirondacks are to be correlated with the Algoman. 



Further remarks were made l)y Messrs. W. S. Bayley and \X. Lindgren, 

 and reply was made by Dr. W. G. Miller. 



NORTH AMERICAN CONTINENT IN UPPER DEVONIC TIME 

 BY AMADEUS W. GEABAU 



(Abstract) 



The history of North America in the Upper Devonic has been worked out in 

 some detail on the basis of physical .stratigraphy combined with paleontology. 



At the opening of the Upper Devonic marine waters were much restricted 

 in North America, the greater part of the United States being exposed to 

 active erosion of the previously deposited Hamilton or earlier formations, as 



