1823.] Geological Society. 307 



A Notice was then read, accompanied with Specimens, by 

 Charles Daubeny, MD. FRS. and MGS. Professor of Chemistry 

 at Oxford, illustrative of the Strata cut through in the Seven 

 Rakes Mine, near Matlock, Derbyshire. 



After describing the qualities of the strata of limestone and 

 toadstone, their dimensions and connexions with each other, and 

 the minerals which they contain, both in veins and regularly 

 disseminated through the mass ; Dr. Daubeny concludes with 

 general observations on the phenomena which they present. 

 He considers that there would be great difficulty in reconciling 

 the facts there observed with that theory which refers to an 

 igneous origin the formation of the toadstone. 



Feb. 21. — Two letters were read, communicated by the Presi- 

 dent, addressed by Joseph Byerly, Esq. to B. Fayle, Esq. con- 

 taining some notices on the Geology of Sierra Leone. 



At Sierra Leone and in the immediate neighbourhood, sienite, 

 porphyry, and basalt, are the predominant rocks. 



Feb. 21 and March 7. — A paper was read, entitled, "Notes 

 on the Geography and Geology of Lake Huron, including a 

 Description, accompanied by Drawings, of new Species of 

 Organic Remains," by John Bigsby, MD. MGS. 



In this paper, the author enters in some detail into a geogra- 

 phical and geological description of the coast and islands of 

 Lake Huron in North America. The greater part of the north- 

 ern shore is composed of primitive rocks ; while the Manitou- 

 line islands which stretch nearly across the centre of the lake, 

 with the southern coast, are entirely composed of secondary 

 calcareous formations. To this paper is subjoined a map of 

 Lake Huron, and plates illustrative of the organic remains 

 which are contained in great abundance in the limestone rocks. 



'March Ml. — A paper was read, entitled, "Observations on 

 the Belemnite," by J. S. Miller, Esq. ALS. communicated by the 

 Rev. W. D. Conybeare, MGS. 



The author commences this paper with an historical sketch of 

 the various opinions which have been entertained with regard 

 to the belemnite, and of the works of those naturalists who have 

 treated of that fossil. He enumerates the various names which 

 ignorance or superstition assigned to it in the earlier periods ; 

 and, lastly, the almost equally discordant and imperfect theo- 

 ries which have been successively advanced on the same subject 

 by writers of a more recent date. Mr. Miller then offers his 

 own opinion on the original structure and nature of this organic 

 body, and adds the reasons and the experiments which have led 

 hi in to his conclusions. He considers the belemnite to have 

 been an animal of the Cephalopodous division of the mollusca, 

 inhabiting a fibrous spathose conical shell, divided into cham- 

 bers connected by a siphunculus, and beyond which shell 

 extended a protecting guard or sheath. Mr. Miller refers the 

 internal radiated texture to its original organic structure, and not 

 to any subsequent process of crystallization. To this paper is 



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