304 ANNUAL OF SCIENTIFIC DISCOVERY. 



tranquilly and slowly deposited. We should also keep in view the important 

 fact, that while one part of the column of strata whose chronology we are 

 studying has been thus rapidly built up by the materials swept into it from a 

 neighboring quarter, other parts of the same column have been reduced in 

 thickness, or even wholly removed, by similar local actions in the opposite 

 direction; and that therefore the strata as they stand give us the measure of 

 a time much less than that in which, as a group, they were actually deposited. 



GEOLOGICAL SUMMARY. 



Tin Ore in California. Dr. C'. T. Jackson, of Boston, in a note to the 

 editor of the Mining Journal, says : 



" In July, 1859, 1 received among a lot of ores, brought me under the suppo- 

 sition that they were of silver, a very rich tin ore, containing sixty and a half 

 per cent of metallic tin in the state of oxide of tin, mostly amorphous, and 

 mixed with brown oxide of iron. It is a curious ore, and would, were it not 

 for its great density, be mistaken for an ore of iron. It was found near 

 Los Angelos, California. The vein is said to be six or eight feet wide. This 

 I think must be an exaggeration ; but it is certainly eight inches wide, as 

 shown by the size of the specimens sent to the Revere Copper Company, in 

 Boston, most of which Mr. Alger obtained for his cabinet, and for the manu- 

 facture of some samples of metallic tin, which he has smelted and refined at 

 a brass-foundery, and got forty per cent of refined tin." We understand that 

 parties have gone to California to make arrangements for opening and work- 

 ing this vein. 



New Mineral containing Boracic Add. At a recent meeting of the Boston 

 Society of Natural History, Dr. A. A. Hayes exhibited a very fusible white 

 mineral from Lake Stiperior, containing twenty -two and a half per cent of 

 boracic acid; it was a silicate and borate of lime, and was obtained from the 

 region of the Minnesota copper mine. Dr. Hayes stated that if this mineral 

 was abundant, it might be collected with commercial advantage. 



Dr. Kneeland observed that the same substance is abundant in the Portage 

 Lake region, and exhibited from the cabinet of the Society a large specimen 

 obtained by him from the Isle Roy ale mine. 



Devonian Hocks and Fossils in Wisconsin. A private communication to 

 the editor of the American Journal of Science states that Mr. J. A. Lapham 

 has recently announced the discovery of rocks near Milwaukie equivalent 

 to the Devonian, and containing remains of characteristic fishes. These 

 remains consist of fragments of bone, teeth, a paddle, with portions of the 

 tuberculated skin or osseous covering. The bed containing these remains 

 overlies the Niagara group, and is the uppermost of the geological series yet 

 observed in Wisconsin. 



Flora of the Older Pakeozoic Rocks. M. Goeppert, the German naturalist, 

 states that the flora of the Silurian, Devonian, and lower Carboniferous 

 deposits comprise one hundred and eighty-four species of plants, including 

 thirty different liiuds of alge. Paleontologists have heretofore supposed the 

 number to be much less. 



Fossil Eggs from the Oolite. At a recent, meeting of the Royal Geological 

 Society (England), Professor Buckman called attention to the discovery of a 

 group of fossil reptilian eggs in a block, of oolitic limestones from a quarry 

 near Cirencester, England. The petrified turtle-eggs from the coral-sands 

 of the Pacific, those of crocodiles in the West Indies, and those of snakes 



