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iSGlEKCR 



[N. S. Vol, IV. No. 99. 



fications of the rocks as had emanated from 

 the European geologists. But it was em- 

 phatically the chief business of the geolo- 

 gist to make a classification of the New 

 York rocks independent of any correlation 

 with the formations of other countries or 

 other States, and the New York column, as 

 they erected it, is constantly achieving new 

 importance, a perpetual memorial of their 

 accomplishments and a monument to their 

 patriotic pride. 



All of the four geologists found subse- 

 quent opportunity to test the validity of 

 their conclusions in other States. Vanuxem 

 had, indeed, undertaken such a correlation 

 before the survey opened ; but of them all, 

 chiefly Prof Hall, who, beginning his cor- 

 relation during the period of his work in 

 this district, has done more than any other 

 to find in the geological structure of other 

 States of the Union corroboration of the 

 work done in New York and to extend its 

 influences over them. 



We should not, on this occasion, omit at 

 least a passing reference to the aid rendered 

 in the survey of the Fourth District by the 

 assistants during the various seasons of 

 work. These were Dr. G. W. Boyd, who 

 died before the work was completed ; Prof. 

 E. S. Carr, of the Medical College at Castle- 

 ton, Vt., and especially the late Prof. E. N. 

 Horsford. Prof. Horsford had been raised 

 among the Seneca Indians of western New 

 York, his home being at Moscow, near the 

 center of the Fourth District. He had 

 graduated from the Rensselaer School in 

 1838, and the season of 1839 was spent on 

 the Fourth District survey. Although this 

 was the only season of his official connec- 

 tion therewith, he had, while still a student 

 at Troy, aided Prof. Hall by conceiving 

 and executing the ingenious geological con- 

 tour map of the Genesee valley accompany- 

 ing the first report on this district. To 

 his intimate acquaintance with this region 

 much of our knowledge of the important 



Genesee section is doubtless due. Through- 

 out all the upward course of later years 

 this eminent man remained, until the end 

 of his life, at all times the cordial friend and 

 active supporter of the Geological Survey 

 of New York. 



It is fitting, too, that we again observe 

 here the influences inspiring these official 

 investigations which emanated from the 

 Rensselaer Polytechnic Institute, at Troy. 

 Van Rensselaer himself, from his own 

 pocket, promulgated the first extended 

 geological exploration of the State ; the in- 

 spiring Eaton, who had delivered, by re- 

 quest, lectures on geology to the Legislature 

 of New York and had even set Governor 

 DeWitt Clinton to collecting fossils, not 

 only promoted the work in all ways, but 

 made it possible by furnishing the right sort 

 of men to do it. Emmons and Hall; Hors- 

 ford and Carr, of the Fourth District, and 

 Briggs, of the First District, were all pupils of 

 his. And it is a pleasure to refer to the fact 

 that the influences of this famous institution 

 upon the geology of New York are in re- 

 newed evidence. The Hon. T. Guilford 

 Smith, of Buffalo, President of this Library 

 Association, a Regent of the University and 

 the chairman of its committee on the State 

 Museum, is also a graduate of the Troy 

 school. 



The geological survey of the Fourth Dis- 

 trict has never been completed. To its 

 determinations there is a constantly grow- 

 ing increment of facts, and from them 

 problems of great interest are ever rising. 

 Now and again novel and important forms 

 of organic life show that we have not yet 

 fathomed the wealth of its sediments, in 

 evidence of which stand the sixty or more 

 species of silicious hexactinellid sponges 

 from the Chemung group, nearly all of which 

 are the discoveries of the last few years. A 

 fauna described by the Canadian geologists, 

 but barely known in this State, the Guelph 

 fauna, has been recently shown by Mr. A. 



