CHAPTER V. 



THE TACONIC SYSTEM. 



MOTIVES OF THE PRESENT INVESTIGATION. OPINIONS OF GEOLOGISTS RELATIVE TO THE TACONIC AND CAMBRIAN 

 SYSTEMS. RELATIONS AND CHARACTERS OF THE HUDSON RIVER ROCKS. ROCKS BELOW AND OLDER THAN 

 THE TACONIC ROCKS. POSITION AND RELATIONS OE THE TACONIC SYSTEM. INDIVIDUAL MEMBERS OF THE 

 TACONIC SYSTEM ; THEIR LITHOLOGICAL CHARACTERS, FOSSILS, SUCCESSION AND THICKNESS, IN NEW-YORK, 

 MASSACHUSETTS AND VERMONT : BLACK SLATE ; TACONIC SLATE AND ITS SUBORDINATE BEDS ; FOSSILS 

 PECULIAR TO THE TACONIC SLATE ; SPARRY LIMESTONE ; MAGNESIAN SLATE ; STOCKBRIDGE LIMESTONE ; 

 BROWN SANDSTONE OR GRANULAR QUARTZ. ROCKS RESTING UPON A PORTION OF THE TACONIC SERIES. 

 THE TACONIC SYSTEM IN MAINE, RHODE-ISLAND AND MICHIGAN. DERANGEMENTS. MINERAL PRODUCTS. 

 REFERENCE TO PLATES XIV. XV. XVI. AND XVII. 



I. GENERAL VIEW OF THE TACONIC SYSTEM. 



§ 1. Preliminary remarks. 

 In consequence of the rejection by Prof. Rogers of a system of rocks which I have deno- 

 minated the Taconic Syste?n, I have been induced to reexamine all the facts and arguments 

 upon which it is supposed to rest. The medium through which Prof. R. has made known 

 his views and the results of his examination of this system, is his Address before the Ame- 

 rican Association of Geologists and Naturalists, at their late session in Washington city, in 

 May of the present year (1S44) , which address is published in the American Journal of 

 Science for July. As my examination, at the time my New-York Report was published, 

 had been confined to New-York, Massachusetts and Vermont, or to the range of hills and 

 mountains extending north from the highlands of the Hudson into Canada, and known as 

 the Taconic and Green Mountain range, I deemed it necessary that an examination should 

 be made also of other fields where the same system of rocks was indicated. Accordingly 

 this last summer I extended my researches into Rhode-Island and Maine. I have not, 

 however, been content with these visits, but have reexamined numerous localities in the 

 fields where my earlier investigations were made. With the additional facts thus acquired, 



