Sept. 5, 1872] 



NATURE 



38; 



shire. The four genera of dendroid Graptolites have a more 

 extensive range, but until now they were only known to occur 

 to_:;ether and in any a'nindance in the (luebec group of Canada. 



The author then stated that he could mw give another locality 

 for these genera. During a recent visit of the Geologists' Asso- 

 ciation to Ludlow and the Longmynds he had found, at Shelve, 

 in the lower part of the Arenig rocks, underlying the great mass 

 of the LUndeilo, a Graptolite zone in which these four genera 

 are represented by species, some of which are identical with, and 

 others nearly allied to, those in the St. David's beds and in the 

 Quebec group of Canada; these beds, and also the Skidd iw 

 slates of Cumberland, being therefore of Lower Arenig age. 



Prof. Harkness, after referring to the labours of Mr. 

 Ilicks, remarked upon the occurrence at so early a period, of 

 so many new forms of life, alluding especially to the discovery 

 of a star-fish. He thought the name Skiddaw woidd be more 

 appropriate for the beds immediately underlying the Llandeilo 

 flags, than .\renig, although he acknowledged that the latter 

 name was one which had been a long tim; in use. — Pi-of. 

 James Hall, of Canada, on being called upon, said that he had 

 examined the specimens on the table and was much pleased to 

 find ths Graptolites from St. David's so intimately allied to 

 those he had described from the (Quebec group ; indeed had he 

 not known where these specimens had been obtained he should 

 have thought that they had really come from some of the beds 

 in Canada. Allowing for differences caused by pressure and 

 cleavage, the resemblance between these and the Canadian forms 

 was trulv remarkable. — Dr. Nicholson said that DHyma^raptus 

 had a wider range than Jlr. Hopkinson had given, several species 

 of this genus being found in the Llandeilo flags in the south of 

 Scotland and elsewhere. — Mr. Hicks, in his reply, said that he 

 was pleased to find that Prof. Hall so thoroughly agreed with 

 his ideas of these beds in regard to their equivalents in Canada. 

 In reference to the remarks of Prof. Harkness as to the name of 

 Skiddaw being preferable to that of Arenig, he said that as 

 some of the rocks in the Shelve district which had for some time 

 gone under the name Arenig, were now proved to be the equi- 

 valent of these beds, he thought it best to adopt this name. — 

 Mr. Hopkinson, in reply to Dr. Nicholson's observation on the 

 genus DHyiHO!^i\iptHs, stated that the species referred to by Dr. 

 Nicholson, in his opinion belonged to a distinct genus to which 

 he had given the name Dicdlograptus, and which differed en- 

 tirely in structure from Didymngraptus. He was very glad to 

 find his views of the equivalence of the St. David's beds, as 

 shown by their Graptolites, with the Quebec group of Canada so 

 decisively confirmed by Prof. Hall. 



Saturday, August l^. — Sur Iss divisions dela Craieen France, 

 lairs limiles et leur fautie, Videntitl de ces divisions des colh dn 

 dllroit, by Prof. E. Hebert. 



The author objected to the divisions of the chalk commonly 

 adopted in England, into chalk vrith flints and chalk without 

 flints. He proposed to subdivide the. chalk according to the 

 characteristic fossils of certain horizons, affirming that the divi- 

 sions thus adopted were constant, and could be applied as well 

 to the English chalk as to that of France. Taking the Gault as 

 the natural base of the chalk, he classed the overlying beds, in 

 ascending order, as follows: — i. Craie ghiuconieusc (Upper 

 Greensand and Grey Chalk) ; 2. Craic h Inoceramits lahialus 

 (Chilk marl, chalk without flint, and part of the chalk with flint) ; 

 3. Craic a Micraster cor-tcstndiuarium (part of the chalk with 

 flints) ; 4. Craie ct Micraster cor-anguiiiiiiii (chalk with flints) ; 

 5. Craie a Bclemnitdla mucroitata (Norwich chalk). 



Between the first and second divisions comes the great series of 

 Sandstones of the Maine; and between the second and third 

 division comes the Hippurite limestone. These beds are not re- 

 presented on the coasts of the English Channel, but at the points 

 where the " breaks " occur there are hardened beds of chalk, 

 often pierced with holes. 



The author showed that the chalk area of the North West of 

 France is traversed by five well-marked anticlinal folds, which 

 ran in a general south-westerly direction, but converging some- 

 what towards the coast. These folds the author identified with 

 some on the English coast. 



Mr. Davidson then made some remarks upon Prof. Hebert's 

 paper, pointing out that the Upper Greensand in parts of Eng- 

 land assumes a much more important character than that given 

 to it by Prof. Hebert. Prof. Phillips, Mr. Godwin-.Au>ten, and 

 Mr. Seeley also took part in the discussion, Prof. Phillips re- 

 marking upon the great good tliat results from meetings of this 



kind, at which geologists of different countries could meet and 

 personally discuss their views. 



Mjniav, August ig. — Three Reports were read at the com- 

 mencement of the meeting. That by J. Thomson, On the Con- 

 tinue/ Investigation of Mountain Limestone Corals, dwelt upon 

 the great difficulty which had been experienced in determining 

 the species and genera of corals. The author showed that all 

 systems of classification founded upon the arrangement of special 

 parts of the coral were artificial and misleading. He had pre- 

 pared careful drawings tracing the coral through the whole of its 

 stages of growth, and he believed that only in this way could 

 we arrive at satisfactory results. 



Prof Duncan and Prof. Jas. Hall both insisted upon the great 

 difficulties that were encountered in classifying corals. It was 

 clear from this discussion that in the corals at least there is no 

 lack of the " intermediate forms " which Mr. Darwin assumes to 

 have existed in all groups of animal and vegetable life. 



Dr. Bryce, in his Report on Eartlujuakes in Scotland, said, 

 that nothing of importance had occurred during the past 

 year, no disturbance of the earth's crust or oscillauon of the 

 lakes had been observed. The attention of the committee had 

 been turned to the remedying of those defects which from time 

 to time are apt to occur with instruments long in use. It was 

 stated that the Seismometer belonging to the Association, which 

 now occupies the lower part of the parish church of Comrie, is of 

 too complex construction for general use. Simpler and cheaper 

 instruments have been constructed by Mr. Geo. Forbes, which 

 will be distributed amongst the stations of the Scottish Meteoro- 

 logical Society, and the results obtained will be detailed in a 

 future report. - 



Mr. W. Jolly's Repjrl on the Discovery of Fossils in certain 

 remote parts of the AWth West Ifighlands, was likewise richer in 

 promise than performance. Certain work had been done in 

 investigating the limestones occurring with the Laurentian 

 Quartzites and Sandstones, but the best part of the report was 

 the announcement that the clergy and schoolmasters of 

 the district hafl entered warmly into the projects, it was 

 therefore hoped that before the next meeting of the Association 

 a good deal of valuable information as to fosdliferous localities 

 would be obtained. 



On the Geology of the Thunder Bay and Shahendotvan Mining 

 Districts on the North Shore of Lake Superior, by H. Alleyne 

 Nicholson, M.D., D.Sc. 



Having recently had an opportunity of accompanyiiig an ex- 

 ploring party to the north of Lake Superior, tlie author had 

 been able to examine geologically the silver-mining district of 

 Thunder Bay, and the gold-bearing district of Shabendowan 

 (sixty miles to the north-west of Thunder Bay). Having 

 described the chief geographical features of Thunder Bay, the 

 author gave an account of the series of rocks known as the 

 "Lower and Upper copper-bearing series. " The chief argen- 

 tiferous lodes were also described, and the more important mines 

 were shortly noticed. The leading geological features of the 

 count.'y between Thunder Bay and Lake Shabendowan were next 

 glanced at, and a detailed account was given of the geology of 

 Lake Shabendowan itself The most interesting rocks described 

 are the so-called " talcose " slates, in which the auriferous lodes 

 are situated. These slates are of Huronian age, and they oc- 

 cupy, along with interotratified and intrusive igneous rocks, a 

 vast area, which extends to an unknown distance north of Lake 

 Shabendowan. Having described their mineral characters, the 

 author expressed his opinion that these " talcose slates " are truly 

 of the nature of bedded felspathic ashes, and that the talc which 

 they often contain is a secondary product developed in them as 

 the result of the metamorphic action to vvliich the whole series 

 has evidently been subjected. It was shown also that these 

 Huronian slates, with their interstratified traps, presented the most 

 striking resemblance to the Borrowdale seris of gr en elates .and 

 porphyries of Cumberland and Westmoreland. The paper con- 

 cluded with a description of the chief auriferous veins which 

 have hitherto been found traversing these rocks. 



On Ortonia, a nao genus of Fossil Tubicolar Annelides, with 

 Notes on the Genus Tenlaculites, by H. Alleyne Nicholson, M. D. 

 Having recently had the oppoitunity of carefully investigating 

 the genus Tenlaculites, the author was lei 10 the conclusion that 

 fossils of diverse zool'igical affinities had een in:luNd undi'r 

 this head (Amer. Jour. Science and Arts, vol. iii. lo>72). The 

 author showed that some fossils formerly referred to Tcntaculites 

 were truly Ptercpods, whilst others were genuine tubicolar an- 



