358 P. E. Raymond — Fauna of the Chazy Limestone. 



There are three well-marked zones in this division, as fol- 

 lows : 



Zone 8 a , the Glaphurus pustulatus zone, is found at the 

 base of Division 3, at Valcour Island, Chazy, Cooperville, and 

 Isle La Motte. The characteristic fossils are : Glaphurus 

 pustulatus, Illmnus globosus, I. erastusi, Isotelus Iiarrisi, 

 Pemopleurides canadensis, Pliomewps canadensis, Amphili- 

 chas minganensis, Pseudosphmrexochus vulcanus, Camarotm- 

 chia plena, Conocardiumbeecheri sp. no v., Bucania sulcatina, 

 and several cephalopods. 



Zone 3 6 , the Camarotoechia, major zone, stands between 

 S a and 3 C and its faunule is a transition between the two. 

 Camarotoechia becomes more abundant and better developed, 

 and fossils, while numerous, become fewer in species. The 

 best development is at Valcour Island. The characteristic 

 fossils are: Camarotoechia plena, C. major, Hebertella costalis, 

 Malocystites emmonsi, Malocystites sp., Pcdmocystites sp., 

 Illmnus globosus* Pliomerops canadensis, Bucania sulcatina, 

 Paphistoma stamineum, and Isotelus obtusum. 



Zone 3 C . The Modiolopsis fabaformis zone. In this zone, 

 Ca?narotcechia plena is abundant, almost to the exclusion of 

 other species. The faunule extends to the top of the formation 

 at Chazy, Grand Isle, and Yalcour Island. The characteristic 

 fossils are : Camarotmchia plena and Modiolopsis fabaformis. 



Section at Chazy, JVeiv York. 



The section at Chazy has a thickness of 732 feet, but the 

 base of the formation is not shown. 



Division 1. — The rocks carrying the fauna of Division 1 are 

 well exposed in the ridges south of the village, near Tracy 

 Brook. The thickness is 365 feet, and judging from the fauna 

 at the base, at least 150 feet of strata are missing. Hebertella 

 exfoliata is" very abundant, especially below the horizon of 

 Scalites angidatus. The latter zone is 217 feet above the base 

 of the exposed section, and is zone l b of the generalized sec- 

 tion. The most common fossils are : 8calites angulatus, Buca- 

 nia sulcatina, Paphistoma immaturum, P. stamineum, and 

 Thaleops ovata. Higher up in the section, 275 feet above the 

 base, is the zone of Lophospira subabbreviata, about 35 feet 

 in thickness. This is zone l c of the generalized section. The 

 gastropods are very abundant in the three localities at Chazy 

 where this zone is exposed. 



Division 2. — The strata of this division are about 195 feet 

 in thickness, and are dark blue, impure nodular limestones, 

 usually full of fossils which are frequently silicified. Stroma- 



