48 PROCEEDINGS OF THE AMHERST MEETING 



Bulletin, page 481, figures au offsetting dike of syenite cutting massive 

 anorthosite ; so that we then became well aware that the syenites followed 

 the anorthosites. 



Meantime interest was directed to the outlier of old crystallines brought 

 up by the great fault near Little Falls, on the main line of the New York 

 Central Railroad. In 1902 Professor Cushing published a preliminary 

 account of it and in 1905 a more elaborate description. To our great 

 surprise, rocks long supposed to be gneissoid anorthosites, from super- 

 ficial examination, proved to belong to the now well recognized syenite 

 series. 



In studying the Pleistocene history of the Hudson-Champlain Valley, 

 Prof. J. B. Woodworth discovered in 1901 the extraordinary basaltic 

 plug or other form of outbreak at Starks Knob, Northumberland, ten 

 miles east of Saratoga Springs, and on the west bank of the Hudson 

 River. Professor Cushing's aid was invoked for the petrographic study, 

 and the paper cited under 1903 resulted. This extraordinary and iso- 

 lated knob of glassy and brecciated volcanic rock is one of the strangest 

 things in New York geology and has in later years been made a small 

 State reservation. To its study Professor Cushing returned in connec- 

 tion with his work in the Saratoga Springs region and published a more 

 detailed description in the Bulletin of the Geological Society in 1913. 

 Its exact nature has not yet been fully determined. 



In 1905 appeared also the "Geology of the northern Adirondack re- 

 gion'" — a very valuable summary of results obtained up to that time and 

 containing comparisons with the work of Kolderup in Norway on rocks 

 extraordinarily like our anorthosites and syenites. Two years later the 

 Bulletin on the Long Lake Quadrangle, already mentioned above, in 

 order to bring the age of the syenites to complete statement, was issued 

 and contained also some valuable observations on a mass of intrusive 

 granite, the Morris granite, which cut both anorthosites and syenites and 

 was therefore later than either. In the same year came the suggestive 

 paper on the "Asymmetric differentiation in a bathylith of Adirondack 

 syenite," in which the outer borders of the great intrusive mass were 

 shown to be higher in silica next the older granite gneisses and lower 

 next the older anorthosite. Absorption and infusion of these wall rocks 

 were believed to cause the contrasts. 



In this same year came the paper on the "Physical oscillations during 

 the Canibro-Silurian in northeastern New York." It indicates the grow- 

 ing interest (already cited above) which Professor Cushing felt in the 

 interpretation and classification of the Cambrian and Lower Ordovician 

 strata. 



