BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 395 



INTRODUCTION 



i Statement of previous investigations 



The status of our present knowledge of the Cephalopoda of the 

 Champlain basin may be understood from the following data. 1 Hall 

 has described in his volume i of the Palaeontology of New York 

 two species of cephalopods from the Beekmantown limestone, both 

 from small fragments, showing neither siphuncle nor living cham- 

 ber, and one only the surface ; and four species from the Chazy 

 limestone, from but one of which the siphuncle is known, from 

 another only the surface and from the remaining two only acci- 

 dental sections. 



On the other hand, Billings has distinguished no less than 49 

 cephalopods from the Beekmantown formation of Newfoundland, 

 Quebec and Philipsburg, 1 only a small number of which have been 

 figured, and has also added 10 species of Chazy limestone cepha- 

 lopods to the five made known by Hall. 



Barrande also has made us acquainted with six species from the 

 Beekmantown formation of Canada and Newfoundland and Whit- 

 field has carefully described and well illustrated an excellently pre- 

 served upper Beekmantown limestone fauna from Fort Cassin in 

 Vermont, but unfortunately has, under the misapprehension that the 

 beds were of the age of the Lowville (Birdseye) limestone, com- 

 pared them rather with Trenton limestone forms than with Billings's 

 Beekmantown limestone species. The same author has also de- 



1 See bibliography at end. 



1 In regard to the fauna of the Beekmantown beds at Philipsburg, 

 Missisquoi eo.. which lie at the northeastern terminus of Lake Champlain 

 in the Province of Quebec, we had no desire to enter the domain of the 

 paleontologist of the Canadian survey in charge of the invertebrate 

 faunas, hoping that he, having the advantage of the use uf the first 

 collections from this locality, of Billings's types and of a thorough 

 knowledge of the Canadian cephalopods, will himself undertake the 

 needed revision and elaboration of the Beekmantown cephalopod fauna 

 of this region. It is specially desirable that the considerable number of 

 species of Orthoceras, described by Billings from that locality, without 

 figures, should be redescribed, referred to their proper genera, and above 

 all figured, to make them available for comparison with those of other Beek- 

 mantown faunas. 



We have only cited here [p. 508] the cephalopod species recorded from 

 Philipsburg by Billings and Barrande; and in the ease of the species of 

 nautiloid forms described by Hyatt, inserted the descriptions. Hyatt's new 

 "pedes of Philipsburg nautiloids have not yet been illustrated nor described 

 in all their characters. 



