94 



HARDWICKE'S SCIENCE-GOSSIP. 



and purple clays). He now describes some cases 

 where the modern watercourse, after flowing for 

 some distance along the line of an ancient (pre- 

 boulder-clay) valley, suddenly deserts that valley and 

 passes through a ravine excavated entirely out of the 

 chalk. These ravines are very different from the 

 other parts of the valley traversed by the same stream, 

 being deep and narrow cuts or trenches with steep 

 wooded sides, and exhibiting more the scenery of 

 Derbyshire vales than that of ordinary chalk valleys. 

 In accounting for the origin of these ravines, Mr. 

 Browne points out that the whole district in which 

 they occur must once have been completely covered 

 by the boulder-clays ; and he supposes that at certain 

 points where the ancient valleys were blocked with 

 high mounds of drift, the streams found it easier to 

 cut new channels through the flanking ridge of chalk, 

 than through the obstacles in front of them. 



Sham Fossils. — At a recent meeting of the 

 Geological Society, Professor Hughes described a 

 branched structure found in the Red and White 

 Chalk of Hunstanton, which has generally been 

 known as Spongia or Siphonia paradoxica. The beds 

 in which this supposed sponge occurs contain 

 fragments of various organisms, including sponge- 

 spicules, but no trace of structure can be found in 

 sections of the Spongia paradoxica. The fragmentary 

 state of the undoubted organic remains would in- 

 dicate that they were drifted into their present 

 position, and therefore a state of things quite unfitted 

 for the growth of a slender branching sponge ; the 

 so-called sponge commonly occurs in layers along the 

 bedding-planes, but frequently rises through the 

 whole thickness of one bed and extends up into the 

 overlying layers. It does not seem likely that it was 

 the root of a Siphonia or some similar organism. 

 Another body which has been also called Spongia 

 paradoxica consists of masses of more crystalline 

 texture, exhibiting upon weathered surfaces a net- 

 work of small ridges enclosing cup-like depressions. 

 These appearances were compared by the author to 

 the weathered surfaces often seen in certain beds of 

 the mountain limestone and in gypsum ; the masses 

 hhow no traces of internal structure. Sections of 

 these bodies show exactly the same characters as the 

 containing rock, except that the material is more 

 compactly crystalline ; it contains the same fragments 

 of shell, &c., and the same sand and pebbles. He 

 regarded them as of concretionary origin, and ex- 

 plained their symmetry of form and regularity of 

 arrangement by their being formed at the inter- 

 sections of joints with the bedding-planes or with one 

 another. Phosphatic nodules occurred in the lower 

 parts of the white chalk, and had these bodies been 

 sponges they would probably have been phospha- 

 tised ; but analyses have shown no marked difference 

 in this respect between their substance and that of 

 the surrounding rock. 



NOTES AND QUERIES. 



Caterpillars Feeding. — In Science-Gossip, 

 for last October, p. 222, the sentence occurs " Since 

 caterpillars only feed in bright light," iS:c. On 

 reading this, it occurred to me that if this statement 

 were intended to include English caterpillars, as it 

 doubtless is, it was incorrect, as I remember having 

 taken caterpillars (what kinds I cannot now call to 

 mind) in the act of feeding by night, when collecting 

 with the aid of a bull's-eye lantern. If some of the 

 readers of Science-Gossip, will state their obser- 

 vations on this point I shall feel greatly obliged. I 

 should also like to ask if any one has noticed that 

 while butterfly larvae show a preference for feeding 

 by day, the reverse is the case with moth larvae, as a 

 general rule ; each thus exhibiting the same preference 

 for light or darkness which it maintains in after life ? 

 ~J. ^H. B. 



Odd Name of Plant. — The parish clerk here 

 tells me of a plant which he calls " Cain and Abel," 

 and which grows in the neighbourhood. The root, 

 he says, consists of two parts, and if thrown into 

 water the one will sink, while the other will swim. 

 Can any of your readers tell me anything about 

 this plant? — yo/iii Haivcll, Inglehy Vicarage, North' 

 allerton. 



Effect of Poison on Hedgehog. — It is 

 commonly supposed these animals are difficult to 

 poison. I once kept one in the house as a pet, at 

 the time we were infested with mice. I laid poison 

 for the mice, composed of strychnine mixed with 

 butter on bread ; by some unlucky chance th£ hedge- 

 hog obtained one of the pieces, and licked off the 

 whole of the butter, with the result that death 

 ensued in an hour or two afterwards. — James F. 

 Robinson. 



Seasonable Notes from Cushenden, — The 

 song-thrush commenced to sing on December 1st, on 

 Christmas Eve, and Christmas morning ; they were 

 singing in concert. Maximum thermometer from 53° 

 to 55° during most of the month. Daffodils and 

 snowdrops well above ground, the latter showing 

 colour. Hive bees flying about on December 28th. 

 Black swan ( Cygmis atrattis) was shot on a lake in 

 Rathlin Island, Nov. 24. Where could it have come 

 from 1—S. A. B. 



Darwin on Instinct. — It is now some years 

 since I first saw the announcement in the " English 

 Mechanic," on the authority of Mr. Darwin, that 

 insects do not "feign death," that the disposition of 

 their limbs is not the same in danger as in death, 

 but merely the same as when remaining motionless. 

 This was so contrary to what I expected at the 

 time that I took every opportunity of observing the 

 attitude of beetles under fear. But for seeing this 

 statement repeated in ' ' Nature " for December 6th, 

 my observations might have been for ever unpub- 

 lished ; but I am now able to say that as far as 

 certain genera of beetles extend, the disposition of 

 the limbs of insects is exactly the same in danger as 

 in death. It is well known that beetles belonging to 

 the genera Anchontcmis, Bembidium and Ptcrostichiis, 

 will generally " take to their heels " when in danger, 

 but sometimes these will remain motionless, at least 

 for a time, as if considering what to do. In neither 

 case does Mr. Darwin say what insects he experi- 

 mented upon, but it is well known that such genera 

 as Cryptorhynchtis, Cceloidcs, Caiihorhynchics, and 



