36 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 19, 



November 19, 1862. 



James Brunlees, Esq., C.E., 5 Victoria Street, Westminster, and 

 M. Auguste Langel, Ex- Secretaire de la Societe Geologique de 

 France, Orleans House, Twickenham, were elected Fellows. 



The following communication "was read : — 



On tJie Cambrian and Huronian Formations. 

 By J. J. Bigsby, M.D., F.G.S. 



Contexts. 



Part I. 



I. Introduction. 



II. Characters of the Cambrian Rocks. 



a. Typical Form and Distribution. 



b. Stages in the Cambrian Epoch. 



c. Stratigraphical Characters. 



d. Organic Elements. 



e. Paucity of Fossils. 



III. Abundance of Life above the 

 Cambrian. 



a. Tracks of Crustaceans. 



b. Phosphatic Coprolites with 



IdnguUs. 



c. Primordial Zone. 



Table I. Synopsis of the Cambrian. 

 Table II. Fossils of the Primordial 

 Zone. 



Part II. 



I. Introduction. 



II. Characters of the Huronian Rocks. 



a. Geological Position. 



b. G-eographical Distribution. 



c. Lithological Characters and 



Typical Form. 



d. Connexion with the Laurentian. 



e. Igneous Intrusions. 



III. Huronian of various Districts. 



a. South Shore of Lake Superior. 



b. Norway. 



IV. Relations of the Cambrian and 

 the Huronian. 



V. Conclusion. 



Table III. Synopsis of the Huronian. 



Part I. — Remarks on the Geographical Conditions op the 

 Cambrian System. 



I. Introduction. — -Some of the following statements, and the con- 

 clusions to which they have given rise, were originally intended to 

 refer, in chief, to the presence or absence of organic remains in the 

 Cambrian rocks ; but, led on by points of interest that gradually 

 presented themselves, the inquiry has been conducted further than 

 was at first anticipated. 



I may perhaps be allowed, for the present, to take for granted 

 that the Cambrian of "Western Europe passes conformably upwards 

 into the Silurian series, with certain changes introduced by altered 

 conditions. Usually these two sets of rocks are mutually conform- 

 able, and pass into each other, sometimes by insensible gradations *. 



It is also true that their unconformity is very frequent, from the 

 local operation of plutonic forces. I shall not stop now to bring- 

 forward proofs of these several assertions. 



I have given as a Table a synoptical list of all the Cambrian 

 deposits known to me, and also other Tables of some use. On these 

 Tables is grounded much of what is advanced in this paper. 



* I ought, however, in limine, to say that the published proofs of this con- 

 nexion between Cambrian and Silurian beds {some of them at least) need 

 revision. 



