74 Scientific Notices — Geology, [Jan. 



experimented upon, and not in any degree to the agency of 

 foreign substance acting as fluxes." — (Annals of the Lyceum of 

 Natural History, New York.) 



Gkology. 



6. On the Geology of Snowdon. 



(To the Editors of the Annals of Philosophy .) 

 GENTLEMEN, 

 Having observed in No. 24 of the Annals, in a paper by 

 Messrs. Phillips and Woods, giving an account of the geology 

 of Snowdon, that the inquiries of those gentlemen were unsuc- 

 cessfully directed in search of a felspathic rock, which had been 

 mentioned to them as existing in that neighbourhood, I have 

 thought it might not be unacceptable were 1 to point out where 

 such a rock may be found, namely, close to the town of Caer- 

 narvon. Here the rock in question forms a conspicuous craggy 

 knot immediately adjoining the north side of the town, which 

 appears to consist entirely of red felspar, with a large intermix- 

 ture of quartz, chiefly in the form of separate crystals. This 

 rock is in its appearance so totally distinct from those in the 

 neighbourhood, that I much regret it should have escaped the 

 observation of a competent observer. From a quarry on the 

 south side of the hill, it appears to rest upon the usual slaty 

 rocks so abundant in that part of Wales. C. C. C. 



We have to apologize to our correspondent C. C. C. for the 

 delay that has occurred in the publication of his communication. 

 The paper was accidentally mislaid. A scientific friend to 

 whom we showed the specimens which accompanied C. C. C.'s 

 letter, having expressed a doubt as to the rock being feldspar, 

 B'Ir. Children has examined a portion of it to ascertain if it con- 

 tain potash. By fusion with nitrate of baryta, 8cc. he readily 

 detected the presence of that alkali. — C. and P. 



Miscellaneous. 



7. Is the Level of the Baltic stationary? 



About half a century ago, the philosophers in the north of 

 Europe entered into an animated controversy respecting the 

 accuracy of an assertion which even then had become very 

 generally credited, that the water of the Baltic is in a state of 

 progressive diminution. Owing to the want of the necessary 

 data, neither party at that period succeeded in establishing their 

 opinion; but the discussion had the fortunate eftect of directing 

 the attention of properly qualified persons to the subject, and of 

 inducino- them to observe from time to time the mean heioht of 

 the water in numerous stations both on the eastern and western 

 coasts. A large body of facts has thus been gradually accumu- 

 lating, and the results of these coincide with such uniformity in 



