68 



SCIENCE-GOSSIP. 



[March 1, 1866. 



GEOLOGY. 



Limited Atmospheric Denudation in the 

 Chalk Districts. — The influence of rain in the 

 chalk as well as oolitic districts of England must 

 be very considerable. But it acts more as a solvent 

 than as a transporting agent. The matter dissolved 

 is re-deposited. It becomes covered with grass, and 

 not one-hundredth part of it ever finds its way beyond 

 the nearest valley or depression. That rain has not 

 altered the general contour of the chalk districts 

 since their rise above the sea, can be proved by the 

 fact that thousands of raised beaches, many of them 

 only a few feet in height, may be found in Wiltshire, 

 Dorset, and other counties. These beaches generally 

 conform in inclination to the surface of the neigh- 

 bouring ground. In valleys they often descend very 

 near to the bottom, thus proving that these valleys 

 Lave not been excavated since the beaches were 

 formed. One of the most remarkable assemblages 

 of these terraces may be seen undulating along the 

 side of a valley to the east of Mere. On the south- 

 eastern escarpment of the vale of Blackmore, they 

 may be seen curving round headlands in successive 

 tiers. These terraces are so intimately associated with 

 the valleys, combes, and escarpments, as to render it 

 evident that all have had a common origin. — D. 

 Mackintosh, in Geol. Mag. 



Eozoon Canadense. — Professor King and Dr. 

 Powney communicated a paper on this subject to 

 the Geological Society, on the 10th of January last. 

 Taking the Grenville Pock as its type, " Eozoonal 

 Serpentine " was defined by the authors to consist 

 essentially of variously-formed granules of chrysotile, 

 or some other allied mineral imbedded in, or inter- 

 mixed with, calcite. Although differing from the type 

 in some respects, the varieties of serpentine which 

 they have examined from Connemara, Donegal, the 

 Isle of Skye, India, Bavaria, and the state of Dela- 

 ware, are considered as belonging to the same section. 

 The serpentine from Cornwall, the Isle of Anglesea, 

 and Saxony, which appears to be devoid of " Eo- 

 zoonal" structure, they were disposed to look upon, 

 but with considerable doubt, as an eruptive rock. 

 The authors stated their conviction that every one 

 of the presumed organic structures of "Eozoonal" 

 serpentine is purely and primarily, mineral or crys- 

 talline. The skeleton they hold to be identical with 

 the calcareous matrix of certain minerals, notably 

 chondodrite, pargasitc, &c. They adduced various 

 considerations and evidence to show that the "pro- 

 per wall " cannot have resulted from pseudopodial 

 tribulation ; and instead of beiug an independent 

 structure, in their opinion, it is no more than the 

 surface-portion of the granules of chrysotile, crys- 

 tallized into an asbestiform layer. The dendritic 

 and other forms, considered to represent the 

 "canal system," were shown to be tufts of metaxile, 

 or some other allied variety of chrysotile ; while 



the resemblance they bear to some which are com- 

 mon in crystalline limestones, also their identity 

 to the imbedded crystallizations of native silver, 

 moss agates, &c, and the total dissimilarity between 

 them and the foraminiferal structures with which 

 they have been homologued, are points which the 

 authors held to be conclusively fatal to the view 

 which contends for such forms being of organic 

 origin ; in their opinion, they are no more than im- 

 bedded "imitative" crystallizations. What have 

 been taken for " Stolons," they were convinced, are 

 for the most part, crystals of Pyrosclerite. The 

 " chamber casts " were considered to be identically 

 represented among both miuerals and rocks — in the 

 former by the grains of chondodrite, pyrallolite, par- 

 gasite, &c, and the latter by the segmented kernels 

 of native copper, zeolites, &c, in eruptive rocks ; 

 also by the remarkable botryodal and other shapes 

 which occur in the Permian limestone of Durham. 

 The authors concluded by offering it as their opinion 

 that "Eozoonal" serpentine is ametamorphicrock; 

 and they throw out the suggestion that it may in 

 many cases have also undergone a pseudo-morphic 

 change ; that is, it may have been converted from a 

 gueissoid calcareous diorite by chemical introduc- 

 tions or eliminations. — The Reader. 



Lake Deposits.— Eor the purpose of obtaining 

 information relative to the Great Irish Elk, or Me- 

 gaceros Ilibemicus, I have visited several localities 

 where remains have been found ; and although it is 

 commonly believed that the bones, &c., are found in 

 t\\ej)eat, as they are reported to have been found in 

 the bog, I have ascertained that this is not the case, 

 upon inquiry and a close investigation into every 

 instance that came under my own observation. I find 

 that the remains of the megaceros are not found in 

 the peat, but in the deposit below the peat. The 

 nature of this lower deposit of course varies with 

 the localities, and may contain either gravel, clay, 

 shell-marl, or diatomaceous earth. As yet, I 

 have not found the remains in either of the first- 

 named deposits ; but I have known of several 

 instances of this occurrence in the shell-marl 

 and diatomaceous earth. The nature of the shell- 

 marl is probably well known to the readers of 

 Science Gossip. It contains a great quantity of 

 beautifully-preserved shells, such as Paludina, Lim- 

 n(ca, Planorlis, &c., all having lost their natural 

 colour, and are now of a chalky white. The diato- 

 maceous earth I have collected from several different 

 localities, and some of the deposits, are very rich in 

 diatoms : when prepared and mounted, they form 

 very valuable slides for the microscope. Should any 

 of the readers of Science Gossip require a spe- 

 cimen of the shell-marl, or the diatomaceous earth, 

 I shall be most happy to supply all applicants who 

 send me the postage, or, what would be better still, 

 a specimen of diatomaceous deposits from other 

 localities. — W. Gray, Mount Charles, Belfast. 



