and the Taconic System* 377 



"The 4tli group only containing two types, Orthis ^nd Te- 

 tradium ; the latter, a polyp, presents no certain sign enabling 

 us to give the epoch to which it belongs. The palseon 

 tological data furnished by Mr. Billings, considered apart 

 from the strati graphical relations yet to be determined be- 

 tween the four groups, lead us to recognize the existence both of 

 the primordial and the second fauna in the calcareous rocks of 

 Point Levis. It is important to remark that these faunas, although 

 occurring in beds very near each other, have as yet oftered but 

 few evidences of connection, since Mr. Billings has only indicated 

 two species common to the groups 1 and 2. 



*' Such are the only deductions which we believe ourselves en- 

 titled to draw from the interesting facts above mentioned. We do 

 not wish to pass the limits of the most prudent reserve in the 

 case, because the facts briefly expressed by Mr. Billings in the in- 

 troduction of his descriptions of the Point Levis fossils, indicate 

 that there are some difficulties yet to be resolved. We observe 

 in the first place, that all these limestones, without distinction, are 

 indicated as being intercalated in a great schistose formation, 

 which has furnished about thirty forms of graptolites, and other 

 analogous fossils, with two Lingulas, one Orthis, one Discina, and 

 one small unknown trilobite. It would be very important to 

 establish whether the species belonging to these schists are found 

 inditFerently at various heights, above, below and between the 

 limestones. Without very precise observations to determine and 

 limit the distribution and the extension of these fossils in the 

 schists, it would be impossible to form an exact idea of the rela- 

 tions which may exist between the re[)resentatives of the first and 

 second faunas contained in these limestones. 



" In the second place, the introduction of Mr. Billings concludes 

 by the following passage which merits special attention. ' It is 

 not yet certain whether the fossils of the limestones are included 

 in the boulders or the paste of the conglomerate.' There exist 

 then in the limestones in question, two rocks of different origins, 

 the one represented by boulders, which we may suppose to have 

 been transported from a distance, and the other formed upon the 

 spot by ordinary sedimentation. W^hile waiting for light upon 

 these points, we will add the following considerations : 



"I. It is established by Mr. Billings that the four groups of fos- 

 sils are each enclosed in a rock distinct in appearance, and that 

 these rocks form different beds, between which there are yet but 



