March 6, 1890] 



NATURE 



425 



where. This state of opinion was partly a consequence 

 of Murchison's early and wonderfully full description of 

 the Silurian rocks and their fossils, which made his work 

 a key to the Lower Palaeozoic of all lands. Sedgwick's 

 Cambrian researches and the palaeontology of the region 

 were not published in full before the years 1852-55, 

 when appeared his " Synopsis of the Classification of the 

 British Palaeozoic Rocks," along with M'Coy's " Descrip- 

 tions of British Palaeozoic Fossils.'" 



But this general acceptance was further due to the fact 

 that the discovered fossils of the Cambrian, from the 

 Lingula flags downward, or the " Primordial," were few, 

 and differed not more from Silurian forms than the 

 Silurian differed among themselves ; and also, because 

 the beds were continuous with the Silurian, without a 

 break. Geologists under the weight of the evidence, 

 American as well as European, naturally gravitated in 

 the Murchisonian direction, while applauding the work of 

 Sedgwick. 



In 1853, Mr. Salter showed, by a study of the fossils 

 (Q. J. Geol. Soc, X. 62), that the Bala beds from Bala in 

 Merioneth, the original Bala, were included within the 

 period of the Caradoc. Sedgwick subsequently (in the 

 preface to the Catalogue of the Woodwardian Museum 

 by J. W. Salter) divided his Upper Cambrian into (i) 

 the Lower Bala, to include the Llandeilo flags (Upper 

 Llandeilo of the Geological Survey, the Arenig being the 

 Lower) ; (2) the Middle Bala, corresponding to the 

 Caradoc sandstone, the Bala rocks, and the Coniston 

 limestone (Geological Survey) ; and the Upper Bala or 

 the Caradoc shales, Hirnant limestone, and the Lower 

 Llandovery (cited from Etheridge, in Phillips's " Geology," 

 ii. Ti, 1885). 



In 1854, the Cambrian system not having secured the 

 place claimed for it, Sedgwick brought the subject again 

 before the Geological Society. Besides urging his former 

 arguments, he condemned Murchison's work so far as to 

 imply that none of his sections "give a true notion of the 

 geological place of the groups of Caer Caradoc and 

 Llandeilo " ; and to speak of the Llandeilo beds, in a 

 note, as " a remarkable fossiliferous group (about the age 

 of the Bala limestone) of which the geological place was 

 entirely mistaken in the published sections of the Silurian 

 System." There were errors in the sections, and that 

 with regard to the May Hill group was a prominent one ; 

 but this was sweeping depreciation without new argument ; 

 and, in consequence of it, part of the paper was refused 

 publication by the Geological Society. 



The paper appeared in the Philosophical Magazine for 

 1854 (fourth series, vol. viii. pp. 301, 359, 481). It 

 contains no bitter word, or personal remark against 

 Murchison. Sedgwick was profoundly disappointed on find- 

 ing, when closing up his long labours, that the Cambrian 

 system had no place in the geology of the day. He did 

 not see this to be the logical consequence of the facts so 

 far as then understood. It was to him the disparagement 

 and rejection of his faithful work ; and this deeply moved 

 him, even to estrangement from the author of the success- 

 ful Silurian system. 



Conclusion. 

 The ground about which there was reasonably a 

 disputed claim was that of the Bala of Sedgwick's region 

 and the Llandeilo and Caradoc of Murchison's. Respect- 

 ing this common field, long priority in the describing and 

 defining of the Llandeilo and Caradoc beds, both geo- 

 logically and palaeontologically, leaves no question as to 

 Murchison's title. Below this level lie the rocks studied 

 chiefly by Sedgwick ; and if a dividing horizon of suffi- 

 cient geological value had been found to exist, it should 

 have been made the limit between a Cambrian and a 

 Silurian system. 



The claim of a worker to affix a name to a series of 

 rocks first studied and defined by him cannot be disputed. 

 But science may accept, or not, according as the name is. 



or is not, needed. In the progress of geology, the time 

 finally was reached, when the name Cambrian was be- 

 lieved to be a necessity, and " Cambrian " and " Silurian" 

 derived thence a right to follow one another in the 

 geological record. 



" To follow one another ; " that is, directly, without a 

 suppression of " Silurian " from the name of the lower 

 subdivision by intruding the term " Ordovician," or any 

 other term. For this is virtually appropriating what is 

 claimed (though not so intended), and does marked in- 

 justice to one of the greatest of British geologists. 

 Moreover, such an intruded term commemorates, with 

 harsh emphasis, misjudgments and their consequences, 

 which are better forgotten. Rather let the two names, 

 standing together as in 1835, recall the fifteen years of 

 friendly labours in Cambria and Siluria and the other 

 earlier years of united research. James D. Dana. 



THE WEATHER IN JANUARY. 



THE month of January, which is generally the coldest 

 month of the year, was so exceptionally warm this 

 year, and in other ways the whole period was so un- 

 usual, that a few of the leading features in connection 

 with the weather may not be without interest. The month 

 opened with a short spell of frost, but, after the first few 

 days, mild weather set in, and continued until the close 

 of the month. 



The stations used by the Meteorological Office in the 

 compilation of the Daily Weather Report scarcely repre- 

 sent sufficiently the weather at inland stations, but yet 

 they will give an approximate idea of the prevailing con- 

 ditions. These reports show that the warmest weather 

 was experienced in the south-western parts of the King- 

 dom, the stations in the north-east of Scotland being 

 about 5° colder than in the south-west of England. On^ 

 the east coast the mean temperatures of Wick, Aberdeen, 

 Spurn Head, and Yarmouth were each about 41° o. 



The following table gives the mean temperature results 

 for a number of stations in all parts of the British 

 Islands: — 



