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K,J 



I'ublislied itionthly by the 



University of the State of New York 



BLILLETIN 327 



JANUARY 1905 



New York State Museum 



Bulletin 77 

 GEOLOGY 6 



GEOLOGY OF THE VICINITY OF 

 LITTLE FALLS, HERKIMER COUNTY 



BY H. P. GUSHING 



PAGE 



Preface 3 



Geographic position -l 



General geology i 



The rocks 15 



Pre-Cambrian rocks 15 



Paleozoic rocks 24 



Structural geology 35 



Dip : 35 



Folds 37 



Faults 3S 



Foliation 47 



Joints 48 



Some oscillations of level during the 



early Paleozoic 51 



Paleozoic overlap on the pre-Cam- 



brian floor 51 



Character and slope of the pre-Cam- 



brian floor 59 



Unconformity at the base of the 



Trenton 0:^ 



Absence of the Chazy formation in 



the Mohawk valley 63 



Sudden thickening of the Trenton 



westward 63 



Comparison with the northern Adir- 



ondacks 61 



Topography 65 



Pre-Cambrian surface 66 



Present surface of the Paleozoic rocks 68 

 Influence of the faults on the topo- 

 graphy 71 



Pleistocene (glacial) deposits 73 



PAGE 



Economic geology 81 



Petrography of the pi-e-Cambrian rocks 85 

 Index 93 



Plates FACE PAGE 



1 Cliff of pre-Cambrian syenite 16 



2 Beekraantown formation 26 



3 Contact of Beekmantown ou pre- 



Cambrian at Diamond hill 28 



4 Beekmantown -pre-Cambrian con- 



tact in West Shore Railroad cut. . . 29 



5 Quarry face at bridge north of Ing- 



ham's Mills. 30 



C Folds in Lowviile limestone at Ing- 

 ham's Mills 38 



7 Dolgeville fault in the bank of East 



Canada creek 45 



8 Utica shale near Dolgeville 46 



9 Fall in East Canada creek near 



Dolgeville 46 



10 North bank of creek south of Cana- 



joharie 62 



11 Fall in creek over the pre-Cambi"ian 



2 miles west of Dolgeville 72 



12 Mohawk river from eastern part of 



Little Falls 72 



13 The Mohawk from the brink of Little 



Falls fault scarp 72 



14 Trenton terrace from Utica shale 



slope to the west 72 



15 East Canada creek \ mile above 



Dolgeville Tg 



NEW YORK STA' 



Mi32m-Ja4-2ooo 



