ON THE INCREASED STRENGTH OF CAST IRON. 



[1853. 



Among bivalve sbells, which chiefly belong to the Arcacidce, 

 a veiy interesting new genus has rewarded examination. It was 

 foinKl that two species resenibhng NuQula in every general char- 

 acter, diti'eied from it importantly by having no internal liga- 

 ment, but a very manifest exterior one; one of these species 

 measures three iiiches across, and from the general analogy of 

 several accompanying species it is believed that this form will be 

 found common in the Silurian rocks, and will include many 

 species now referred to JSfucula. It might be called Ctenodonta. 

 Of the same family also, a Lyrodcsma (a genus with radiating 

 teeth beneath the beak and synonymous with Acliiiodontu, Phil- 

 lips) is closely allied to a Trenton limestone species. There is a 

 new genus probably belonging to the Arcacidce, but only pos- 

 sessing two or three anterior te;th; but the collection does not 

 include any Ai'iculce, or indeed any other of the usual Silurian 

 genera of this order, and of the seven or eight lamellibranchiate 

 shells none appear quite identical with those from New York ; 

 but, as miglit be e.\pected, the common Brachiopoda of this lo- 

 cality ai-e those most abundant also in the Trenton limestone. 

 Ortlds triceiiaria, Coni'ad, swarms here, as does also Leptcena 

 flitcrta, Hall, a shell very like the common L. alternata of the 

 Trenton limestone, but reversed as to the convexit}' of the respec- 

 tive valves. But the lattei' shell, so abundant in New York, 

 does not occur here at all. Atrypa hemiplicata, Hall, and A. 

 increbrescens ai-e tolerabl}' frequent; and there are two or thi'ee 

 other species of Orthis, and some small plaited and smooth Tere- 

 bratulce, which require further examination. 



The Bellcrophona, two of which are probably identical with 

 New York s])ecies, are those of the lowest or chazy limestone, 

 namely, B. (Bucania) sidcatina, Emmons, and B. rotundata, 

 Hall. The group to which these two belong is that of which 

 the English B. dilatatus is a familiar type, the whorls scarcely 

 enveloping each other, and the mouth wide and trumpet shaped. 



There is however a true Bellero^jkon so like B. ohlectus, Phill., 

 from the Ludlow rocks of Pembrokeshire, that, but for its treble 

 size, it might be taken for it. 



Perhaps one of the most interesting of the m^llusks is a large 

 Chodora, quite new to America, and not yet described as such 

 from Biitain. On attentively comparing the American, Irish 

 and North Welsh specimens of this fine shell, which measures 

 two inches across, I can find only trivial \ariations. It does not 

 require a new specific name, having been figured from an imper- 

 fect specimen as Atrypa transversa hy Portlock. It is interest- 

 ing to find this species (which of couise, as a Pteropod, had 

 ready means of migration) in the two countries. 'J here are 

 but few other species identical with those of Great Britain, but I 

 think I i-ecognise Turbo Irochhntus, and perhaps T. tritorqua- 

 ius, McCoy, as common to the two regions. 



Of the Cephalopoda, the remarkable two-edged Orthoceras, 

 called Goniocerns anceps by Hall, is a Black River limestone 

 R]5ecii,'S. C'l/rtoceras is common, both smooth and ornamented; 

 G. anmilatum and C. lameUosum, the same with those of Tren- 

 ton; Orthoccras arcuo-Iiratum, bilincatum, and laqueatum, Hall, 

 are Trenton limestone species; and lastly, there are two species 

 of Ormoreras, Stokes, the larger of which is in all probability 

 O. temiijilum, Hall, a sjiecies both of the Black River and Tren- 

 ton beds. 



Srhhncrin>is nodomis, \h\\\, n't \\v?. 'Yrvniow limestone, is the 

 common crinuid: its steins are very characteristic. 



Among the corals, one or two species of Strcptolasma, appa- 

 rently tlu; same as those of New York, and the branched \aric- 

 ties of Favositcs hjcoperdon, accompanying those before men- 



tioned ; and we may here notice the ReceptacuUies, already des- 

 cribed by Hall, but not I think identical with B. Neptuni of 

 Europe. The fine series brought home bj' Mr. Logan shows all 

 the structural characters; — the circular expanded form and cup- 

 like centre, — the surface composed of rhomboidal plates, which 

 cohei'e by lateral processes, and which are the flattened ends of 

 separate and equidisfcmt columns Unfortunately the entire 

 structure is replaced b}^ cycloidal silex, but perhaps it will by 

 careful polishing enable us to see if it be really a coral, some- 

 what of the character of the Tubiporidcc. 



To crown alt these are slabs full of the large Asapkus (Jno- 

 telus) giyafi, the characteristic trilobite of the Trenton rocks. 



Upper Silurian Rocks. — Ascending the Ottawa to the head 

 of Lake Teraiscamang and so crossing the granitic axis of Cana- 

 da, the first fossiliferous rock that presents itself is of a totally dif- 

 ferent character to that last described, as stated by Mr. Logan in 

 his Report of Progress for 1845. 



This limestone is weathered like the last; its sil;c!eous fossils 

 also stand out in bold relief; and one of the most common is the 

 characteristic crinoid of the Trenton limestone, Schizocrinus 

 nodosus, at least I believe I am correct in this reference. But 

 along with this are abundance of Favosiles golhlandica, Stroma- 

 topora striatella, C y athophyUum, a HelioUtes [Poriles), with 

 small tubes; Syringopora {^Harrnodites) with Hulysites caten- 

 vlatus ( Catenipora eschuroidcs), and Strornbodes striatus, 

 Milne Edwards, fossils characteristic of the Niagara and Onon- 

 daga limestones, and in America never found in the lower i-ocks; 

 with these occur Atrypa reticularis in plenty, a Terebratrda 

 with three raised plaits, and very rarely a LepAmia or Stropho- 

 mena. One or two spiral shells recall the shapes of some of 

 Hall's species of Holopea, but are too imperfect for identification ; 

 and there is a long spiral shell, like Marchisonia gracilis. JSn,- 

 crinvnis punctatus is the only trilobite. 



The most striking shell perhaps is a species of Ormoccras, the 

 short broad siphuncles of which are well preserved, while the 

 shell has decayed, and tliese so much resemble those figured by 

 Dr. Bigsby and Mr. Stokes in the Geological Trausaetiotis, 2n'd 

 series, vol. i. pi. 30, figs. 4, 5, 6, 7, that we think thei-e can be no 

 doubt of their identity. And it is very interesting, as bearing on 

 the question of age, that these were found at Drummond Island, 

 the only limestones of which are Upper Silurian. 



Indeed the whole aspect of this collection, small as it is, is a"! 

 strikingly Upper Silurian as that of the former one was Lower 

 Silurian. The preponderance of the Catenipora, Favosites and 

 Slromaiopora, &c., is characteristic of the higher rocks, and the}' 

 are associated with Penlanerus oNongus (the characteristic fos- 

 sil of the Clinton group, which may be regarded as the base of 

 the upper division), and this shell in America is far more limited 

 in its vertical ranc-e than it is in Britain. 



On the Increased Strength of C-tst-iron, Produced bj' tlie 

 Use of ImpioveJ Cok::. 



BV Vf. FAIRBAIUN, ESQ., M. IKST. C.B. 



At the Institution of Civil Engineers, a highh' interesting pa- 

 per on this subject was lately reail by Mr. Fairbaim; it commenc- 

 cil with a counnunication from Mr. Grace-Calvert, on the sub- 

 ject of an itnproved system of depriving tlie fuel, whether used 

 in blast furnaces or in icmelting cupolas, of the deleteriotis sub- 

 stances by which the qualit}- of the iron was deteriorated; or of 

 the adaptation of the system to blast furnaces, when using coal 

 for smeltinjr iron ores. 



