236 Astronomical Society. 



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, M.D. M.G.S. 



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

 graphical and geological description of the coast and islands 

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

 northern shore is composed of primitive rocks, while the 

 Manitouline islands, which stretch nearly across the centre of 

 the lake, with the southern coast, are entirely composed of 

 secondai'y 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 lime- 

 stone rocks. 



March 21. A Paper was read, entitled " Observations on 

 the Belemnite." By J. S. Miller, Esq. A.L.S. Communicated 

 by the Rev. W. D. Conybeare, M.G.S. 



The author commences this pnper with an historical sketch 

 of the various opinions which have been entertained with re- 

 gard 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 theories 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 na- 

 ture of this organic body, and adds the reasons and the ex- 

 periments which have led him to his conclusions. He con- 

 siders the belemnite to have been an animal of the Cephalopo- 

 dous division of the Mollusca, inhabiting a fibrous, spathose, 

 conical shell, divided into chambers connected by a siphun- 

 culus, 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 subjoined an enumera- 

 tion and description of the various species of belemnites, ac- 

 companied by plates illustrative of their form and structure. 



ASTRONOMICAL SOCIETY OF LONDON. 



March 14. The papers read at this meeting were: 

 1st. On the Determination of the Resultant of two Forces 

 or Pressures applied to a Point of Matter, by means of a func- 

 tional Equation. By Dr. Meikleham, Professor of Natural 

 Philosophy in the University of Glasgow. 



2d. 



