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 I 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 System , 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 (1844), 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, 
