FIFTH REPORT OF THE DIRECTOR I908 



27 



PALEONTOLOGY 



Early Devonic faunas. The work of the paleontologist on this 

 subject, which has been in process during a number of years, has 

 now been brought to a conclusion so far as concerns its scope as ex- 

 pressed in volumes i and 2 of Memoir 9. The second volume of 

 the memoir is now entirely printed. The contents of volume 1 

 were largely devoted to a close comparison of the Devonic faunas 

 of Gaspe, Quebec with those of New York. In volume 2 these 

 comparisons are extended to the faunas of Dalhousie, X. B., north- 

 eastern and northern Maine. The data available for these studies 

 have been somewhat comprehensive and are drawn from regions 

 which have heretofore elicited but slight attention from geologists. 

 The array of facts therefrom presented has thus in considerable 

 measure the value of new knowledge and the conclusions of 

 broader import bearing on the origin and dispersion of the faunas 

 and also indicative of the ancient geography of the continent are 

 here restated. 



General conclusions 



From the considerations given based chiefly on the analyses of 

 the faunas we may justly draw some reasonable inferences as 

 to the connections of the northeast basins of the early Devonic 

 with those to the south and west. Such inferences can be stated 

 only as probable for there still remains in eastern Quebec and 

 northern Maine an extensive area whose structure is insufficiently 

 known to afford entire security in indicating the boundaries of 

 these passages. Some of these inferences have already been set 

 forth in their proper place but to restate them briefly we conclude : 



1 There was a definite and clear passage from Gaspe into Xew 

 York and the more southern Appalachians during the period of 

 the Helderbergian, where a well denned element of the Helder- 

 bergian flourished in the St Alban beds at the base of the Gaspe 

 limestone series. 



2 A similar open way existed at approximately or actually the 

 same time, connecting the Dalhousie beds of northern Xew Bruns- 

 wick with the Helderbergian of New York. 



3 That these two passages seem to have converged and united 

 into one toward the west and south, for while each carries a clear 

 predominance of Helderberg species, the two have comparatively 

 little in common, the fauna of one representing essentially one 

 congeries, that of the other a different congeries of species which 

 are apparently commingled in Xew York. 



