210 ANNUAL OF SCIENTIFIC DISCOVERT. 



shown. To fix tliem, the author dusts some finely dried pigment 

 over the surface of the still moist plate, and then fixes this by some 

 transparent varnish. 



FOSSIL CONTENTS OF MINERAL VEINS IN THE CARBONIFEROUS 



LIMESTONE. 



Mr. Charles Moore read a paper, at the 1868 meeting of the 

 British Association, upon the above subject, in which he said his at- 

 tention had been called to it from the fact that the mineral veins in 

 many instances contained organic remains, by a study of which it 

 was not only possible to arrive at the age of the veins in their 

 several districts, but also to some extent the physical conditions 

 associated with them at the time they received their contents. 

 After referring to his published views on the veins occurring in 

 the carboniferous limestone in the Somersetshire and South Wales 

 district, he gave the results of his daily examinations of lol dif- 

 ferent samples derived from the mines of Cumberland and York- 

 shire. Of those loJ: samples, he had found organic remains more 

 or less abundantly in not less than 80, — a fact sufficient to show 

 that, as a general rule, they might be found in almost every vein 

 if a careful examination be given to its contents. Among the 

 organic remains, chief interest would attach to the presence of 

 Valvata and other fresh- water shells, often in great abundance 

 and in districts wide asunder, showing most conclusivelv a con- 

 nection between the north of England mines and lodes of fresh 

 water which must have found their way into the veins of some 

 neighboring source. Of vertebrata, he had obtained teeth and 

 scales of Fetalodus, CtejiopiycJtius, etc., etc. ; foraminifera were 

 generally ver}^ rare, while entomostraca of several species were 

 the most constant organisms, encriuites excepted. 



GLACIAL ACTION IN MAINE. 



Dr. N. T. True, of Bethel, Me., at the 1868 meeting of the 

 American Association, read a paper on " Phases of Glacial Action 

 in Maine at the Close of the Drift Period.'' His theory, whicli was 

 drawn from observation of the remarkable formations known as 

 *' horse-backs," which are to be found in every part of the State, 

 is summed up in a continental elevation, followed by ice, then a 

 subsidence, followed by heat and the melting of the ice. 



Large basins worn in the hard granite are found, while the 

 pieces of rock which have been detached from the ledge present 

 the appearance of having been torn ofi:' by an immense pressure, 

 which was undoubtedly produced by icebergs moving b}^ glacial 

 force over the fiice of this country. The basins were probably worn 

 in the hard granite by this same force acting for along time in one 

 particular place. Some idea of the length of the ghicial period 

 may be obtained by comparing these cavities with those worn in 

 blocks of marble by constant action of water and gravel under a 



