i8 9 3. NOTES AND COMMENTS. 33 i 



An important memoir on the Jurassic rocks of the Southern 

 Jura by Dr. Attale Riche has lately been published (Annates de 

 I'Univevsitc de Lyon, vol. vi., 1893). The beds described are the 

 Bajocian, Bathonian, and Callovian, which the author includes as 

 "Jurassique Inferieur." In this respect he departs from the ordinary 

 grouping, which places the Lias in the Lower Jurassic. The local 

 details furnished by the author are valuable ; while his Comparative 

 Table of formations, which places beds with Ammonites parkinsoni on 

 a level with those yielding A . arbustigerus, is calculated to yield matter 

 for discussion. In this way A. parkinsoni comes in both Bajocian 

 and Bathonian formations. He ends the Lias with the zone of 

 A. opalinus, and includes the representatives of our Cornbrash in the 

 Callovian. The work shows the difficulties that attend all attempts 

 at very minute correlation of strata in different areas. 



A short paper just published by Mr. W. H. Dall is likely to be 

 overlooked as of purely palaeontological interest unless his last para- 

 graph is read. Mr. Dall, writing on a subtropical Miocene fauna in 

 arctic Siberia (Proceedings of the United States National Museum, vol. xvi.), 

 remarks that " it is perhaps very late in the day to refer to the hypo- 

 thesis which explained the warm water Old Miocene of the North 

 Atlantic shores by assuming a shifting of the polar axis, so that the 

 pole at that time would have been situated somewhere in central 

 Siberia. That hypothesis has few, if any, friends at the present time ; 

 but it may not be amiss to point out that, if it were necessary to put 

 a quietus on that moribund speculation, the presence of a warm water 

 Old Miocene in eastern Siberia, such as our present fossils indicate, 

 would be quite sufficient to prove that no polar conditions in the 

 modern sense could have existed there during that epoch of geological 

 time." 



Subtropical, or at least warm-temperate, Miocene plants have 

 already been obtained in Greenland and Spitzbergen, and the North 

 Pole was evidently completely encircled by a warm belt such as no 

 shifting: of the axis will account for. 



Authors should, if possible, give a clue in the titles of their 

 papers to the subjects dealt with. In the Geological Magazine for 

 October, we find the first part of a paper on " Some Cretaceous 

 Pycnodont Fishes," by Mr. A. Smith Woodward. Imagine our 

 surprise when we discovered in it accounts of Kimmeridgian, 

 Portlandian, and Purbeckian Fishes ! Some Neocomian and 

 Cretaceous forms are also described. 



