588 Annals of the Carnegie Museum. 



1885. Seri.v, H. M. a new Genus of Chazy Sponges, Strephochetus. American 

 Journal of Science and Arts, Vol. 30, third series, p. 357. 



In this paper is described a new genus of free calcareous sponges, com- 

 posed of concentric layers containing minute twining canals. 



1S86. Wai.cott, Charlp:s D. Second Contribution to the Studies of the Cambrian 

 Faunas of North America. IJullelin of the United States Geological Sur- 

 vey, No. 30. 



Refers to the Chazy formation in its relation to the Cambrian and to the 

 (Quebec group. 



18S7. Ami, H. M. ( )n the Occurrence of Scolilhus in the Rocks of the Chazy For. 

 matton about (Jttawa, Canada. Ottawa Naturalist, Vol. i, pp. 65-74, 81-88. 

 Not seen. 



1S8S. Ami, H. M., and SoWTKR, T. W. E. The Chazy Formation at Aylmer, F. 

 (^. Ottawa Naturalist, Vol. 2, No. I, pp. II-15. 

 Not seen. 



1888. Brainerd, Ezra, and Seely, H. M. The Original Chazy Rocks. Amer- 

 ican Geologist, Vol 2, p. 323. 



In this paper the authors give a detailed section and map of the outcrops 

 of the Chazy at the typical locality, Chazy, New York. The thickness of 

 the formation there is stated at 740 feet. This is the first paper to give the 

 true thickness of the formation. 



1890. Dawson, J. W. On Burrows and Tracts of Invertebrate Animals in Paleo- 



zoic Rocks and Other Markings. Quarterly Journal of the Geological 

 Society, Vol. 46, pp. 595-617. 



Describes and figures I\usi(:h>2ites greiivil/tiisis which he attempts to show 

 is a crustacean burrow. The specimen is from the Chazy formation at the 

 Grenville Cana', Canada. 



1891. Braineri), Ezra. The Chazy F"ormation in the Champlain \'alley. Bulle- 



tin of the Geological Society of America, \'ol. 2, pp. 293-300. 



The author gives detailed accounts of the sections at Valcour Island, Isle 

 La Motte, and Crown Point, and makes observations on the Chazy, High- 

 gate, St. Armand, and Cornwall sections. The thickness of the formation 

 is greatest at Valcour Island, where it reaches 890 feet, and decreases 

 toward the south, being 305 feet at Crown Point and 59 feet at Orwell. 

 This paper is of the utmost importance and certain portions will be quoted : 

 "Along its western border (Lake Champlain) are steep, high hills of 

 Archean, apparently the former shore of the old Silurian sea. '' . . . "West- 

 ward from Cornwall, toward Lake Champlain, the beds of the Chazy rapidly 

 decrease in thickness. The same fact is noticeable southward from Valcour 

 Island along the lake shore. The top and bottom of the formation are the 

 first to disappear. Neither the ' Rhynchouella ' beds nor the ' slaty lime- 

 stone' are to be seen south of Valcour. The Lower Chazy and Upper Chazy 

 contract to small j^roportions and finally disappear. Then the Middle Chazy 

 begins to contract, and also disappears." 



