322 FOSSILS. 



The graptolites seem to be allied to the species found in Utica slate, and have been found at Appletree 

 Point, and Lonerock Point in Burlington. The Stromatopora (?) was found in the Hudson River lime- 

 stone in Orwell. It is a genus of coral, which has never been found elsewhere below the Niagara or Clinton 

 groups of the upper silurian. The specimens are obscure, yet seem to be related to Stromatopora. Much 

 better specimens of the same fossil were found in the Eolian limestone, which is very near the Orwell, 

 limestone. 



In the east part of Bridport, in a limestone which we have referred to the Hudson River Group, chiefly 

 from its nearness to the red sandrock, we were shown specimens of the Chaetetes lycoperdon, by Rev- 

 Augustus Wing, of Stockbridge. The same gentleman called our attention to numerous fossil shells in 

 undisputable Hudson River limestone, which belong to the genus Euomphalus. These remains are all 

 imperfect, but they are very numerous in certain localities, and probably a little research will bring to 

 light specimens of such perfection, that their specific characters may be ascertained. They 

 have been found at Benson, Orwell (particularly near the village), east part of Bridport, 

 Snake Mountain, and upon the town line between Monkton and Ferrisburgh, upon the 

 west side of Mount Fuller. 



The Triarthrus Beckii has been already described under Utica slate. It is poorly repre- 

 sented in Fig. 235. It has been found at Snake Mountain, and upon Appletree and Lonerock 

 Points in Burlington, in the slates underlying the red sandrock series. Inasmuch as Prof. 

 Emmons supposes this trilobite to be altogether different from the Triarthrus Beckii of the 

 Hudson River Groups, we deem it proper to state his views in regard to it, as expressed 

 ^ v himself in his work on American Geology, Vol. I, Part II, pages 115, 116. 



"Axops TKILINEATUS, Calymene Beckii (Hall.) Crust granulated, cephalic sbield semi- 

 circular, with its anterior and lateral edges turned upwards, posterior angles rounded, facial suture 

 beginning at the outer angle of the cephalic shield, and runs nearly parallel with the anterior margin to the 

 middle lobe, when it turns at a right angle and runs parallel with that lobe; eyes undistinguishable, body 

 composed of seventeen or eighteen rings, narrowing very gradually to the caudal extremity; pygidium a 

 flat expansion of the crest and is provided with a single ring; axis narrower than the lateral lobe, rings 

 seventeen, each of which is separated by a groove about as wide as the rings. Axis armed by a row of 

 short spines; lateral lobes provided with a row of tubercles or prominences along the median line; margins 

 of the rib groove run parallel as far as the tubercle, when they diverge; tubercles become obsolete towards 

 the tail; caudal shield very small and provided with one, or at most two rings. 



" This fossil has been confounded by Mr. Hall with the Triarthrus Beckii (Green), Calymenc Beckii. 

 He has been misled by the row of short spines along the middle Jobe or axis, which it is well known exist 

 in that species. It differs, however, from the Triarthrus in every other character; in the number of 

 abdominal and caudal rings, the proportions of the subdivisions of the head, the granulations of the 

 integuments and the row of tubercules along the lateral lobes. So palpably different were the heads of the 

 Atops and Triarthrus, that a committee of the American Association decided they were different from the 

 heads alone; and since this decision was made the specimen figured has been found, which sets the question 

 at rest." 



GEOLOGICAL CHARACTER OF THE ISLANDS, POINTS AND HEADLANDS OF 



LAKE CHAMPLAIN. 



We introduce here the geological character of the different islands, points, and headlands, of Lake Cham- 

 plain, in a separate table. As most of these points arc lower silurian, this is the proper place to present it. 

 It will be of service to those that wish to follow in the path we have traced among the interesting localities 

 of fossils, etc., upon the lake. Details respecting the position of the rocks and interesting facts, will be 

 found under the several formations. These observations were taken from the notes of all the different 

 Principals and Assistants. To give symmetry to this list, the geological character of points of the shore 

 belonging to New York are given, many of which were examined for this purpose. We commence at the 

 south end of the lake and proceed northwards. 



