138; * PROCEEDINGS OF THE BOSTON MEETING 



SIGNIFICA:SCE of the middle SILURIC in. AMERICAN AND EUROPEAN 



GEOLOGY 



BY AMADEUS W, GRABAU 



(Al)Stract) 



Tlie classification of the Siluric is considered, and the reasons for regard- 

 ing the Salina as the only American representative of the Middle Siluric are 

 given. The status of the Shawangunk conglomerate is considered and the 

 evidence for an extensive hiatus between the Salina and the Bertie, which 

 latter is of Upper Monwan age, is discussed. In Europe, only Lower and 

 Upper Siluric beds are known corresponding to the Niagaran and the Monwan 

 respectively of the American classification. The Middle Siluric is everywhere 

 represented by a hiatus. 



Presented without notes. 



GEOLOGY OF THE PORTSMOUTH BASIN, MAINE AND NEW HAMPSHIRE 

 BY ALFRED WAISTDKE ^ 



(Abstract) 



This basin is a downfaulted block bounded by gneisses of an unknown age, 

 and consists of a series of fine-grained sediments, probably Upper Carboni- 

 ferous in age, which are cut by sub-alkaline and alkaline intrusives. The 

 easterly striking sediments, occurring in tight folds overturned to the south- 

 east, have been grouped into two formations — a lower one, the Berwick gneiss, 

 and an upper one, with the Kittery quartzite and Eliot phyllite as lower and 

 upper members. The intrusives are made up of dikes which range in com- 

 position from diabase through to the alkaline varieties, such as the tinguaites 

 and paisanites, and of subjaceat bodies, which include both sub-alkaline and 

 alkaline types. Elevated shorelines, delta deposits upon marine clays, and 

 reworked glacial drift indicate a Quaternary marine transgression. Sub- 

 merged tree stumps indicate a relatively recent dro-wning of the shoreline. 



Presented with lantern slide illustrations, without notes. 

 Discussed by Prof. C. W. Brown. 



PALEOZOIC SECTIONS SOUTH OF JAMES BAY 

 BY MEBTON Y. WILLIAMS 



(Abstract) 



The Paleozoic outcrops exposed in the beds of the Mattagami, Abitibi, and 

 Moose rivers indicate the presence of red shale and basal arkose, which prob- 

 ably represent the Queenston shale and older beds of the Ordovician system ; 

 shales (red and gray, with interbedded dolomites) and gj^psum, evidently of 



Introduced by R. A. Daly. 



