REPORT OF TEE CHIEF ASTRONOMER 515 



SESSIONAL PAPER No. 25a 



one represented in the fossiliferous horizons. On that question there is at 

 present absolutely no light. It remains to note in Dr. Girty's general summary 

 of the status of the fossiliferous beds themselves. He writes: — 



' In the way of explanation I may state that, owing to the imperfect 

 knowledge of most of our western Carboniferous faunas and to the poor 

 state of preservation in which the fossils occurred, it was not possible to 

 make positive identifications in most cases. 



' Faunally, I would be disposed to arrange these collections into several 

 groups. Lots 1512 and 1514 are closely related and represent, perhaps, 

 the only strongly marked fauna in the collection. Lot 1500 is also rather 

 diagnostic. Lot 104 is moderately extensive, but is not strongly character- 

 istic. It seems to differ considerably from either of the two faunas just 

 mentioned. Of the remaining collections, which are faunally very limited, 

 two groups can possibly be made. One of these comprises such lots as 

 consist only of very abundant and very large crinoid stems (lots 69, 70, 

 71, 72, 129, 1506 and possibly 98), or crinoid stems and cup corals (lots 

 1498 and 1513), or cup corals alone (lot 1509). The other group shows 

 only fucoidal markings (lots 1510 and 1511). 



' The most natural geologic section with which to compare these 

 faunas is that of northern California. The sequence of the Carboniferous 

 formations there consists, in ascending order, of the Baird shales, the 

 McCloud limestone, and the Nosoni formation (formerly the McCloud 

 shales). The Baird shales have usually been regarded as of Lower Carboni- 

 ferous age and the McCloud and Nosoni as Upper Carboniferous. All three 

 have extensive and characteristic faunas. There is nothing among your 

 collections which suggests the Baird or McCloud. The most strongly 

 characterized of your faunas (lots 1512, 1514, and 1500), however, have 

 much that is similar to the Nosoni. At present I am disposed to correlate 

 the two horizons. Lot 104 is less certain, but possibly belongs to the same 

 group. The lots furnishing only corals and crinoids differ widely from 

 1512 and 1514, but they might readily come from a specialized bed in the 

 same formation. Nothing positive can, however, be stated about them. 

 As to the three remaining lots, the data do not warrant suggesting any- 

 thing whatever. On the whole, from the little that I understand of the 

 stratigraphic relations and from the relationship manifested by the most 

 marked of your faunas with that of the Nosoni formation, I am disposed 

 to correlate all your beds in a general way with the latter. They may 

 contain measures younger or older than the Nosoni, but from the absence 

 of the well-marked Baird and McCloud facies it seems probable that none 

 of the horizons from which your collections came is as old as the McCloud.' 



In conclusion, it may be stated that the great volcanic member, the Chilli- 



?ack Volcanic formation, which will be specially described, is of distinctly 



Jpper Carboniferous age. Just above and just below this member are con- 



'rmable limestone beds containing samples of the fauna discussed by Dr. 



25a— vol. ii— 334 



