14 PROCEEDINGS OF THE ASSOCIATION OF 



mains would to some extent indicate,) or as di/Tercnt members of 

 one formation — the mountain limestone. 



In reply to some remarks by Prof 11. D. Rogers, Prof Locke 

 obsei-ved, that he did not undertake to be the advocate of absolute 

 equivalency, but merely to i)oint out the agreement and disagree- 

 ment of certain formations in America with similar ones in Enrope. 

 He was of opinion, however, that certain points of equivalency must 

 be admitted, as for example granite, the great coal formations, &c. 



Prof. Mather proposed th6 subject of " Joints of Rocks " for 

 discussion during this session of the Association ; and Prof. 

 H. D. Rogers proposed that of " Fossil and Recent Infusoria." 



The Association then adjourned until 4 o'clock this afternoon. 



April 6th, 1841, 4 o'clock, p. m. — The Association met pur- 

 suant to adjournment, Prof. Locke in the chair. 



Mr. William C. Redfield exhibited specimens of fossil 

 shells, from the tertiary marl-beds at "Washington, Beaufort 

 county, North Carolina. 



Ml'. R. stated that these beds, which are about sixty miles from 

 the Atlantic, are found from fifteen to twenty feet below the adja- 

 cent surface, and two or more feet lower than the usual level of 

 Pamlico river and sound. The fossils are in a good state of preser- 

 vation, and are supposed to belong to the miocene period. 



Prof. Locke read a paper " on a new species of Trilobite, 

 found at Cincinnati, Ohio," and called by him Isotelus maxi- 

 mus. 



This species is characterized by its elliptical terminations, and 

 by a thorn-like process about one tenth of the length of the animal, 

 projecting backwards from each angle of the shield, similar to an 

 Ogygia. He exhibited casts of one entire specimen, nine and thre'e 

 fourths inches in length, and of a fragment of another of double 

 that size in linear dimensions, which of course must have been nine- 

 teen and a half inches long — the largest specimen hitherto known 

 to have been found. 



Dr. Jackson stated that ti'ilobites had been found in the lime- 

 stone at the mouth of St. Croix river. He then exliibited the 

 following specimens of minerals and fossils, namely : 



Fossils from the limestone belonging 1o the red sandstone 

 group of ]\Iachias, Maine. A new mineral from Unity, New- 

 Hampshire, which he has analyzed and proposes to describe 

 under the name of Chlorophyllite. A new mineral from Na- 

 tick, Rhode Island, described by him under the name of Ma- 

 sonite. Tin ore from Jackson, New Hampshire, near the cel- 

 ebrated Notch of the White Mountains. Sulphuret of copper 

 and iron mixed with tremolite, from the town of Warren, N. H. ; 



