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HARDWICKE'S SCIENCE-GOSSIP. 



Wood, near Sidmouth, Veronica montana is found 

 in abundance of a reddish purple colour. In a 

 meadow near it, by the river Otter, I also met with 

 several plants of Carclamine pratensis bearing 

 double flowers, like those seen by " A. E. G.," near 

 Worthing. Convolvulus arvensis has also been 

 pointed out to me, with double flowers, on a chalk- 

 bank, at Siirewton, South Wilts.— W.Moyle Rogers. 



How to Take Impressions of Plants.— The 

 following is a simple method of taking impressions 

 of plants, requiring only a large sheet of paper, 

 some olive (or other) oil, black-lead, ashes, and 

 resin (or colophony). The paper is first lightly 

 oiled on one side, then folded in four, so that the 

 oil may filter through the pores, and the plant may 

 not come into direct contact with the liquid. The 

 plant is placed between the leaves of the second 

 folding, and in this position pressed (through other 

 paper) all over with the hand, so as to make a 

 small quantity of oil adhere to its surface. Then it 

 is taken out and placed carefully on white paper . 

 another sheet is placed above (since two impres- 

 sions can be taken), and the plant is pressed as 

 before. On now removing it an invisible image 

 remains on the paper. You sprinkle over this a 

 quantity of black-lead (or ashes, or other fine 

 powder), and distribute it in all directions, as in 

 applying sand to writing; the image then appears 

 in all its parts. With an assortment of colours the 

 natural colours of plants may be reproduced. To 

 obtain fixity, resin is added to the blacklead (pre- 

 viously) in equal quantity ; the impression is fixed 

 when it is exposed to a heat sufficient to melt the 

 resin. 



GEOLOGY. 



Intra-glacial Paleolithic Implements. — 

 Mr. S. B. J. Skertchley, E.G.S., announces the dis- 

 covery by himself, at Brandon, in Suffolk, of Palaeo- 

 lithic flint implements in brick-earth underlying the 

 well-known "chalky boulder clay," associated with 

 bones and fresh-water shells. The implements 

 belong to the crude type. 



The Phosphate Beds'of South Carolina. — 

 Most of our geological readers will be acquainted 

 with the fossils from the Carolina phosphate beds. 

 Dr. Leidy remarked, at the Philadelphia Academy of 

 Sciences a short time ago, that these phosphate 

 beds were remarkable for the irregular admixture of 

 multitudes of fossils of different ages, from the 

 early Tertiary period inclusive down to the present 

 epoch. So far the fossils in many respects are 

 similar to those found in the phosphate nodules of 

 our Suffolk Red Crag beds. Dr. Leidy said that the 

 Carolinian phosphatic beds appear to have had their 

 origin from the Eocene rocks beneath. These_have 



also contributed numerous remains of marine 

 vertebrates, especially of zeuglodonts, reptiles, and 

 fishes. Mingled in the sand and clay, with the 

 phosphatic nodules and bones of Eocene animals, 

 are innumerable remains of cetaceans, sharks, &c, 

 of the Miocene and Pliocene periods. A still further 

 mingling of quaternary shells and bones with these 

 two sets renders the confusion all the greater. The 

 teeth of the great shark (Carcharodon megalodon) , 

 as well as of the extinct mastodon, point out the 

 fact that these creatures survived in America to a 

 later period than they did in Europe. 



The Mechanism of Production of Volcanic 

 Dykes and on those of Monte Somma.— A paper 

 read before the Geological Society, by R. Mallet, 

 Esq., E.R.S., E.G.S. The author stated that in 

 1864 he made a careful trigonometrical survey of 

 the escarpment of Monte Somma, especially with 

 reference to the numerous dykes by which the 

 rocks composing it are intersected. He described 

 in detail the phenomena of direction of the dykes, 

 especially as regards the axis of the cone of Vesu- 

 vius; to this direction he gives the name of 

 orientation. Of twenty-seven dykes ten presented 

 an approximately vertical line, whilst all the rest 

 had a sensible dip or " hade." The dykes are in 

 no cases intersected by coherent beds of lava, but 

 in one instance the top of a dyke was stopped by 

 such a bed. Many of the dykes bifurcated or 

 branched, and frequently two dykes intersected 

 each other at considerable angles. These and other 

 circumstances prove that the dykes were produced 

 at different and successive ages. Many of them 

 were fractured and displaced iu consequence of 

 movements of the mass of rock traversed by them ; 

 and these dislocations are regarded by the author 

 as indicating the vast extent and force of the in- 

 ternal movements, due principally to gravity, which 

 are constantly taking place in the mass of volcanic 

 cones. These movements greatly influence the 

 position of the dykes, and render it difficult to 

 ascertain that which they originally occupied. The 

 dykes thin out at various heights, and their superior 

 and northern terminations were found not to reach 

 the existing surface, notwithstanding the amount 

 of denudation that has taken place ; and hence the 

 author concludes that they never reached the sur- 

 face of Somma, when it was the wall of an active 

 volcano. The author further indicated a process 

 by which beds or plates of lava descending the 

 slopes of a volcano may change their direction, and 

 becoming imbedded in the detritus accompanying 

 or following them, may, to a greater or less extent, 

 simulate dykes, although in this case the two sides 

 of the plate will present the differences always 

 seen in the upper and uuder surfaces of a bed of 

 lava. The orientation-lines of five or six of the 

 observed dykes were said to pass approximately 



