PKEFACE. 



In describing the few generic types given in these pages, I am 

 acting as pioneer for my friend Mr. E. Billings, who wishes me to 

 share this portion of his task, and I very willingly join with him, 

 and with Professor James Hall, in commencing this series of 

 Decades. The drawings and plates have been executed for some 

 time past. 



In a short memoir on the fossils collected in the limestone at 

 Pauquette's Rapids, on the Ottawa River, which was presented to the 

 British Association in the year 1851, and appended to Sir William 

 Logan's paper on the Rocks of Canada, it was stated, that the lime- 

 stone included fossils characteristic of all the lower divisions of the 

 New York system, from the Calciferous sandrock to the Trenton lime- 

 stone inclusive. With regard to the lowest of these strata, a correction 

 may be made, for, when more closely examined, the Euomphalus 

 unlangulatus of that rock appears to be somewhat different from the 

 Ottawa shell referred to it. The other limestones are certainly 

 represented ; — the Chazy by the peculiar genus Maclurea, and the 

 Birdseye and Black-river limestones by some identical corals and 

 shells. With the Trenton formation, as might be expected, the 

 affinity is greatest ; and the beautifully preserved fossils, silicified 

 in a pure calcareous matrix, and weathered extensively, permit of 

 accurate comparison with the figures and descriptions of those from 

 the United States. 



In this collection from a single calcareous band, we meet with 

 the Bellerophon sulcatinus and B. rotundatus of the Chazy limestone ; 

 Murchisonia ventricosa and the Stromatocerium from the Birdseye. 



