GEOLOGY 



The work under the direction of the state geologist during 

 the past fiscal year has, as usual, been prosecuted both in the 

 field and the office, and its results are summarized in the fol- 

 lowing pages. 



The large geologic map of the State described in Museum bul- 

 letin 56 was issued in June 1902, and has been received with much 

 appreciation in all quarters. 



In pure geology the survey of the crystalline rocks of the 

 Adirondacks has been continued by Prof. H. P. Cushing, whose 

 field work of the past season was devoted to the mapping of 

 the Long lake sheet of the topographic atlas, some 30^ of its 

 area being mapped in detail. The rocks are mainly igneous 

 intrusives and it was expected that detailed mapping would 

 throw light on the complicated relations of the anorthosite, 

 syenite and granite intrusions to one another. The portion of 

 the sheet covered during this first season was, in the main, 

 away from the anorthosite boundary, and showed syenite as 

 the prevailing rock, more or less involved with granite. On 

 the west slopes of Mt Morris this syenite is much cut by a 

 granite, which is clearly younger. The syenite is found to vary 

 much in composition, in grain and in degree of foliation, speci- 

 ally toward its peripheral portions. In Litchfield park it be- 

 comes very acid, grading into a granite, which is found to be 

 cut by another granite, apparently the same as that which 

 cuts the syenite about Mt Morris. Kunning north from Litch- 

 field park, and forming the ridges between Little Simons and 

 Follensby "ponds, is a considerable area of a different granite 

 rock, more gneissoid and richer in dark silicates than the pre- 

 ceding, but no exposures could be found which disclosed its 

 relations to the surrounding rocks. 



Two unexpected and very interesting little examples of 

 anorthosite outliers were found in Litchfield park, some miles 

 distant from the main mass. One was but meagerly exposed 

 and gave no clue as to its relations to the surrounding rocks, 



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