438 THE CANADIAN NATURALIST. [Vol. vi. 



like Stromatopora, which present, according to Dawson a struc- 

 ture intermediate between the Eozoon of the Laurentian and the 

 genera Parkeria and Loftusia of the Cretaceous and the Eocene. 

 The details are taken from Dr. Dawson's recent prCvsidential 

 address to the Natural History Society of Montreal, in May, 

 1872, where he has announced some of the results of his studies, 

 yet in progress, on the earlier foraminifera. 



In 1856 the late Prof. Emmons described [Amer. Jour. Sci. 

 II, xxii, 389] under the name of Palaeotrochis, certain forms 

 regarded by him as organic, found in North Carolina in a bed of 

 auriferous quartzite, among rocks referred to his Taconic system. 

 Their organic nature has also been maintained by Prof. Wurtz, 

 but from my own examinations, I agree with the opinion 

 expressed by Prof. Hall, and subsequently supported by the 

 observations of Prof. Marsh, [Ibid. II, xxiii, 278 ; xvl. 217] 

 that the forms to which the name of Palaeotrochis has been 

 given are nothing more than silicious concretions. 



As regards the geological horizon of the series of strata to 

 which Sir William Logan has given the name of the Quebec 

 group, the Sillery and Lauzon divisions have as yet yielded 

 to the paleontologist only two species of Oholella and one of 

 Lingula, Our comparisons must therefore be based upon the 

 fauna of the Levis limestones and graptolitic shales, which 

 have already been compared with the Middle Cambrian or Fes- 

 tiniog group of Sedgwick, by the combined labors of Billings 

 and Salter. The former has moreover carefully compared this 

 fauna with that of the lower members of the New York system ; 

 in which the succession of organic life appears to have been very 

 much interrupted. Thus, according to Mr. Billings, of the 

 ninety species known to exist in the Chazy limestone of the 

 Ottawa basin, only twenty-two species have been observed to pass 

 up into the directly -overlying Birdseye and Black-River lime- 

 stones. The break between the Chazy and the underlying Cal- 

 ciferous sandrock, in this region, is still more complete ; since, 

 according to the same authority, of forty-four species in the 

 latter only two pass up into the Chazy limestone. This latter 

 break in the succession appears to be filled, in the region to the 

 eastward of the Ottawa basin, by the Levis limestone ; which has 

 been studied near Quebec, and also near Phillipsburg, not far from 

 the outlet of Lake Champlain. This formation (including the 

 accompanying graptolitic shales,) has yielded, up to the present 



