GEOLOGY, 243 



the result of an examination of seventy-one species of tertiary mol- 

 lusca from Jamaica, showing that twelve are still living, and that 

 twenty-eight are common to the tertiary beds of Jamaica and St. Do- 

 mingo. The same relation between those deposits had been found to 

 exist by Dr. Duncan through a comparison of the corals. The " Pa- 

 cific " affinity of many of these shells and corals was noticed as confir- 

 matory of a conclusion arrived at by the author in a former paper ; and 

 it was shown, from the occurrence of tertiary beds on the Panama Isth- 

 mus at a height of 250 feet above the sea, that the complete separa- 

 tion of the Atlantic and Pacific Oceans did not take place until after 

 the commencement of the tertiary period. 



Formation of Coral Islands. M. de Rochas announces to the 

 French Academy the result of his inspection of coral islands in various 

 parts of the globe, as not in harmony with the accepted theory on this 

 subject. That theory assumes that the polyps which build up the 

 earthy substance of these islands cease to build when the edifice 

 reaches the low-tide mark ; and that the subsequent deposits, from the 

 waves dashing over its surface, completes the elevation. M. de Rochas 

 thinks that the first part of this statement is correct ; the second part 

 is incorrect. He attributes the elevation above the surface of the water 

 to volcanic agency. " No coral island without an upheaval, which 

 pushes above the surface of the water the coral abandoned by the 

 polyps ; " that is the formula of his experience. Me finds the surface 

 free from the attrition and fractures which would result from the 

 throwing over them of pebbles and sand by the waves ; and he also 

 finds the coral, in many places, where no upheaval has raised it above 

 the surface, remaining in precisely the same position in which it was 

 observed long ago, with no accumulation of debris on its surface. 



Height of Mount Shasta, California. -- A careful and elaborate series 

 of barometrical observations recently made by the State Geological 

 Corps of California has fixed the elevation of Mount Shasta at 14,440 

 feet. Previous to this the height of Shasta had been variously estimat- 

 ed. Fremont's estimate was 15,000 ; Williamson's, in the Pacific 

 Railroad Survey, 18,000; and Wilkes, 14,350. 



The Mineral Statistics of Great Britain for 1862, as given by Mr. 

 Hunt of the School of Mines, are as follows : the quantity of gold ex- 

 tracted was 5,209 ounces; silver, 686,123 ounces; tin, 8,476 tons; 

 copper, 14,843 tons ; lead, 69,031 tons ; zinc, 2,151 tons ; coal, 81,638,- 

 338 tons ; representing a total value of 34,691,037. 



Tin Ore in Maine , At a recent meeting of the Boston Society 

 of Natural History, Mr. A. E. Verrill called attention to the circum- 

 stance, that tin ore (cassiterite) has now been found at three locali- 

 ties in Oxford Co., Maine, in similar situations ; in each case, in a vein 

 consisting in great part of albite, passing through granite ; and in two 

 of the localities at least, it is intimately associated with these small crys- 

 tals of zircon, both often being seen in the same specimen. At the lo- 

 cality in Greenwood that he had discovered a few years ago, the asso- 

 ciated minerals were zircon, pyrochlore and magnetite, all in small 

 crystals like the tin ore itself. At Mount Mica, in Paris, so well-known 

 for its rare minerals, he had found the ore in 1854 in a mass weighing 

 about five pounds, and also in small crystals. Specimens from this lo- 

 cality had already been exhibited to the Society. At this place the 



