110 



NEW YORK STATE MUSEUM 



In the following pages the general arrangement 1 is similar to 

 that adopted in most of the geologic text books. The introduc- 

 tory matter is newly written and also the larger portion of the 

 chapters on the Archaean and Cambrian rocks. The Cambrian 

 below the Potsdam was not known as such in Lincklaen's time 

 and was not discussed by him. The description given herewith is 

 taken chiefly from the work of C. D. Walcott, Bulletin of the 

 U. S. Geological Survey No. 81. The Palaeozoic strata of New 

 York from the Potsdam to the Catskill were well known to the 

 members of the original geological corps, Hall, Mather, Emmons 

 and Vanuxem and Lincklaen's interpretations of their published 

 results were so satisfactory that in the present work his descrip- 

 tions of these formations have been used, so far as practicable, 

 with such corrections and additions as were necessary to express 

 our present knowledge. 



In making these corrections, the statements of the original 

 corps of geologists and of the later geologists who have worked 

 in New York have been freely quoted. 



The descriptions of the Mesozoic and Cenozoic ages have been 

 newly written. 



Lincklaen's descriptions of the fossils of New York are not 

 wholly accurate in the light of modern knowledge and in order 

 to save time in revision and the considerable space needed for a 

 proper presentation of the subject, they have been omitted. Bef- 

 erences are, however, given to the proper authorities and it is 

 hoped that the State Palaeontologist may prepare a handbook on 

 this important subject. 



The chapter on economic geology is abridged from Bulletin 15 

 of the New York State Museum, with some additions. 



The illustrations are, to a large extent, new and it is believed 

 that the representation of typical sections and exposures by 

 photographs is more satisfactory than by the more common dia- 

 grams. 



It is to be regretted that it was not possible to make a series 

 of photographs complete in each geologic series, but no opportun- 



