« ROCK COLLECTIONS. 005 



New-York system. The whole of the rocks of the State end with an adjoining table, which 

 contains specimens of the New redsandstone, and its crystaUine associate, commonly known 

 as Trap rock. 



Besides the arrangement of superposition or succession by tables of the different rocks or 

 groups, the tables themselves, in all cases where two or more divisions exist, exhibit likewise 

 the succession by specimens ; those in the first row, or nearest the spectator, being the lowest 

 in the group, and the succeeding rows rising in their order to the upper surface of the group. 

 Thus, the four divisions of the Onondaga-salt group are arranged in their respective order. 



As the tables do not average more than about sixty specimens, there are upright cases, 

 lettered and numbered, to correspond with such tables as are abundant in different kinds of 

 rock or fossils, so as to give the required illustration. 



The specimens collected in this district for the colleges, since the Reporter has had it in 

 charge, are now ready for distribution ; amounting to thirty-nine boxes divided into seven 

 parts, the parts lettered from a to g, and each part numbered according to the number of 

 boxes therein, having the mark '3 D' or 'Third district' upon each box. The collection made 

 for the same institutions by Mr. Conrad and Dr. Boyd, the first year of the Survey, before 

 the third and fourth districts were altered, will form a part of the collection of the fourth 

 district. 



In closing this Report, the writer directs attention to this negative fact : that no notice 

 appears in any of the reports which have come from him, of services, kindness, and attentions 

 having been received by him from the inhabitants of the third district, although a like notice 

 is common in most works of the kind. The desire is, that the omission shall be well undet- 

 stood to arise from no other cause than the wish not to particularize ; and to mention the 

 names of all with whom he has been placed in any of these relations would, in accordance 

 with the opinion which he holds, be incompatible with the plan of this work. Since the com- 

 pletion of the outdoor part of the Survey, and while engaged in preparing and printing its 

 results, he can not, however, refrain from expressing his obligations, in common with those 

 of his associates in the Survey, to Mr. John Patterson, the gentleman employed by the 

 State Printer to supervise the proofsheets of the work, for the care and attention he has 

 devoted to his task ; an employment for which his general acquaintance with literal and natu- 

 ral science renders him eminently qualified. 



There being no time before that part of the Report which relates to the Hamilton group 

 went to press, to have a wood-cut of the Hamilton agelacrinite prepared, it is placed here at 

 the conclusion of tlic entire work. 



Geol. 3d Dist. 39 



